If it said "your next end step" instead of "during upkeep"
This card would definitely see play.
I would rather see lands transform into enchantments, artifacts or creatures. That way it would help against prison decks.
Hopefully we see a land that transforms into a planeswalker. Yeah, that'd be the day.
All that said, I still like it. This set has a few cards for Commander, so far.
I found the card quite interesting, actually.
Maybe not an obvious powerhouse, but it seems to me a card that would be quite good in the workshop matchup. I think the flipside would be mostly an island and that is perfectly fine. The additional ability just grabs the attention and distracts from why this card can be good.
It functions similar to a Dark Confidant there, except that it doesn't die to Walking Ballista. It finds you land drops turn after turn, which can be hugely important. Workshop have little to interact with it.
Finally, when it flips it is an additional land drop, which hardly ever seems to be mentioned. Just as an island it would have been good to get an additional land out, but this also has the ability to break open the late game.
I am actually quite excited about this card. I don't think there is an obvious home of or it. Neither do I think it is a new staple, but I do like it as a role player and think that it is deceptively powerful. Blue doesn't usually get mana acceleration in the form of additional land drops. So getting one at two mana with some card filtering in between seems quite nice.
Lastly. You can play a second copy once the first flips.
The land searching is indeed on the front side, by flipping away nonlamd cards.
After some limited (totally not representative) testing in a The Deck style build, I've found the card to be somwhere between okay-ish and library-of-alexandria-level-backbreaking. The fast meta/shops builds are definately not the meta it wants to be in though, unless you get lucky and drop it t1 on the play. Although there are many more cards that are good t1 on the play.
The front side is rather skill intensive. What do you do when you're low on mana and find a ponder? I found force of will when on an empty hand and 4 mana (opponent also in topdeck mode).
The turn it flips is usually amazing, as you get both the filtering and an additional land drop, with blue mana as well!
I also expected that the ability on the land would be less important than the actual mana and filtering, but it is very dominating. It allows you to play pure control, giving you something to do with your mana when there is nothing to counter. In addition: finding a Force of Will is just about the greatest, turning one blue card in your hand into a free counter. It's surprisingly worthwile to just see 4 and try to find a free counterspell when you don't have any (or get business when your opponent does nothing).
That said, it is the lack of speed on this card that makes it less appealing currently. And seeing good cards with the front side of this card is kind of awkward.
Also fuels delve spells nicely (as if they needed any more help).
All in all, I'll continue testing it. Maybe in another build or in multiples. The card is intruiging.
I found force of will when on an empty hand and 4 mana (opponent also in topdeck mode).
Don't know the exact game state nor the opponent, as this may change everything. But in this scenario isn't it just way better to dump the FoW and flip to Azcanta to start drawing 2 per turn?