Apparently this card didn't get a spoiler post (unless I missed it). Time to rectify that.

Everyone has their own process for evaluating cards. Some people look to draw comparisons to existing cards. Personally, I hate that approach. Very few cards are functionally equivalent and therefore justify comparisons. What do I mean? Disenchant and Fragmentize have the same function (destroying artifacts and enchantments). Disenchant was a playable card in Vintage and because Fragmentize did the same thing, it makes sense to compare these cards to establish whether or not they are playable. In the end, it was clear that saving a mana was worth the timing and targeting restrictions. Jace, Vryn's Prodigy is not functionally equivalent to Snapcaster Mage or Merfolk Looter, and so evaluation by comparison missed the mark on the card. It makes much more sense to evaluate Jace in the context of how it functions first before any sort of comparisons are made.

Why bring this up? Well, it's very tempting to view The Antiquities War as a bad Tezzeret baby. After all, the card is combination of Tezzeret's abilities in Enchantment form. You do that, and you end up quickly dismissing the card. Tezz the Seeker mostly sees play because it searches up Time Vault and wins the game that way. Tezz Agent of Bolas doesn't really see play at all. Tezz, Antiquities War doesn't serve as an obvious upgrade of either and so many players dismiss it and you end up without a Spoiler thread on TMD.

Let's step away from comparisons and focus on what the card does: In an artifact heavy deck, it impulses for 2 turns then wins the game. It's immune to Revoker effects, can't be attacked by creatures, doesn't require that much set up (it digs up 10 power of attackers. It does get hit to Pyroblast but then most of the cards you are running in Blue suffer from that (well, not Karn...more on him later). That's...not bad right? Suspend 2: win the game for 4 mana with a couple of artifact impulses? I thought not and so I built a deck around this and streamed it. If you missed that (I apologize...the videos get mangled due to twitch's copyright filter), to summarize: the card was a very solid win condition in the Thoughtcast, Mox Opal, Seat shell. It's immune to rod, you can drain into it pretty easily, and it fuels itself. It's less powerful than Paradoxical Outcome but the cards are complimentary - If you lack the artifacts for PO (which happens a lot), TAW will find some for your next turn. After you've PO'd, dumped a ton of artifacts into play, then passed back with counterspells to stop your opponent for one more turn, TAW wins the game. Synergy. I frequently had issues with Tendrils being a dead card when not comboing out. Or drawing a Blightsteel with my Tinker and then hating life. Or getting my Time Vault Dacked. TAW doesn't have those issues and therefore provides several advantages to the Thoughtcast PO deck.

My next stop with the card will be that list above (I was trying to make Damping Sphere work too, but I feel those go in different decks). I hope to stream it on Friday, but until then I hope this prompts some discussion on a card that has until now flown under the radar.

Edit: here is the rough draft of the first list

I really like this card for all the reasons you said. The inevitability it provides you once resolving is massive and could make it very impactful. I wish this card were printed back in the heyday of Turbo Tezz, it would have been a great addition there. I would try something with even more artifact mana, like Grim Monolith, Voltaic Key, and maybe even a Chrome Mox or two.

4-1'd with a 4x TAW deck (with PO). It was very good, with the exception of getting Shopped one round.

Btw, Sagas are not legendary. It actually can be pretty relevant when you are building up to PO or Chapter III.

Stuff I agree with, and other opinions: That stream was awesome man. I was watching both sides, you and the fellow who kept drawing Library T1 against you every game. That was so enjoyable. And even though you didn't get the better of the matchup, I think your deck was better than the short run results, and it was great to watch play. Thanks for doing it.
In general, if for no other reason than that I am a quibbly and unpleasant bastard, I feel compelled to say this about card evaluation. I agree with you that pretty much every card is different (ie. not functionally equivalent). I think that's why comparison is used so much. That's why I use it. (Why is bolt "good" and chain lightning "bad"? Because the one is just a hair better than the other. And nobody needs 5 bolts.) An ecosystemic analysis is good. It produces good results in terms of describing why some things see play and other don't. (I personally have a terrible instinct for what cards are "good" and what aren't. I test a lot, and I look at a lot of decklists and data, because when it comes to just eyeballing cards, I basically have a learning disability.)
That said. I'm not so into Antiquities War. I won't go into the reasons. I'm sure you've heard them all by now. I am into Damping Sphere. That one makes me think of an agro deck right away. I'm looking forward to what you come up with there.

I'm glad you enjoyed the stream. I actually appreciate when people take the time to express and explain differing points of view as in the end it helps me to understand both the belief I hold and what others believe. Or maybe we ware both quibbly and unpleasant.

The example of Lighting Bolt vs. Chain Lightning is a good example of when comparisons between cards is warranted. I'm not saying all use of comparisons is bad, but I think people overuse and misuse it. Bolt and Chain Lightning do pretty much the same thing - they are functionally equivalent. Most cards that are spoiled do not have functional equivalents, at least not the interesting ones. They tend to do new things, and when you compare them to other cards, you tend to lose sight of the novelty and end up explaining why comparisons see or don't see play.

My preferred approach is to ignore comparisons most of the time. Instead I try to focus on what a card does and then try to imagine it in the ideal shell. For instance, TAW in this 26 artifact, PO deck. Often times, the deck you construct falls to pieces or doesn't have much of a shot in current the metagame, and you can move on - If the card at its best isn't good enough, why look at it when it's sub-optimal? That's my rationale at least and I find it conducive to brewing new decks and exploring different approaches. Though sometimes you end up down the rabbit hole and need a good disagreement to pull you out.

About The Antiquities War, you are not alone in your skepticism. I'd say most people are pessimistic about the card from the people I've talked to. I will say that you don't really need to be "in" to just one card and if you like Damping Sphere perhaps you should look to TAW in your brews. Aggro decks can use DS to buy time to close out the game, and that's kinda the same thing as TAW, where you need 2 turns and then get to attack for 20.

@chubbyrain Not to get off topic here, but thanks for the reply. And again keep up the good work.

As for damping sphere, am I just way off in seeing it in some sort of fishy agro deck? It makes me want to play mana dorks and nonsense like merfolk. And it strikes me that an exceedingly underreported aspect of the card is that multiples stack on the second ability. I imagine something with 4 caverns in it and 4 dampings... But I'm probably wrong since I usually am.

I think my issue with the Antiquities war is somewhere at the intersection of its CMC, it's speed, and its shared weakness to similar strategies.

You mentioned it is weak to REB, which is of course true and relevant, but it is also weak to Hurkyls recall, Shattering Spree, Ancient Grudge, etc. It does not help shore up any weakness that this type of strategy was not already weak against, which is the primary reason those other strategies do not see play very often.

I also think comparing it to Tezz is fair, but unlike your comparison I think Tezz is still better, and that he just does not see play because there are other strategies people find to be better/more powerul. They both do very similar things but with a few variations. Tezz can draw you 2 artifacts in a row over 2 turns just like this card, but Tezz can also win you the game 1 turn after he hits the table with his ultimate unlike this which is on a fixed timer. Tezz can also make 5/5s 2 turns in a row and conceivably give you 15 power worth of swings by his second turn in play, which depending on how your opponent has fetched/used fastbond/Misstepped you can actually be a turn faster clock with the same strategy.

That being said, part of me believes that Tezzeret is criminally underplayed. He can be powered out super early, like turn 2, and if you had a solid draw sometimes win you the game on turn 3. I played him in affinity in legacy with Forces back in the day, and that deck would regularly drop him turn 2 on the play with the help of springleaf drum and opal put you in a position to flat out win turn 3. That is a format that does not even have true moxen, lotus, Academy, Ancestral, Timewalk, Sol ring, or Crypt.

I am always looking for a way to play a mono blue deck and this card plus Karn make my dream a reality once again. I think Tezzeret the Seeker with 2 or 3 of these gives a path to play mono blue without going all in on control.

Stasis and Voltaic Servant are good with TAOW and Karn as well. Untapping a blue mox or seat of synod or your 20/20 token are all gg.a

@hierarchnoble I think the version I gave him could have better used and protected TAW. Chalice of the Void on 1 is particularly effective at stopping Pyroblast and there is just something cathartic about attacking with a 5/5 Chalice.

That variant has moved more towards Karn and PO and away from Damping Sphere and TAW, but I plan on revisiting those cards later in a deck that is more "prisony".

Edit: This isn't unusual. I often try to build multiple synergies and strategies into decks, then adjust based on how games play out. Turns out, Karn making multiple Marit Lage tokens is pretty good...