@Smmenen I agree with you on your assessment of this set. I like it a lot. There isn't any game changer as far as I can see, but Oh am I GLAD we don't have a Monastery Mentor or Dack Fayden or whatever every set. Abrade is a possible staple, and there are a lot of other great role players for the format in the mid-long term. I really like it.
And thanks for the Tragic Lesson bit. I posted it here during spoiler season and the trolls couldn't contain themselves. Nice to see you have the same inclinations regarding it as I do.
A few comments on cards:
Scavenger Grounds: it's reusable if you have another deserts like Hostile Desert or whatever. So it's not a 1 time thing IF you actually play another desert (Hostile Desert is probably the only playable one - there's is the bad combo with Dunes of the Dead for you to get a 2/2 zombie, but that's just bad I guess).
Bloodwater Entity: there is 1 use I thought for it that is to return miracles to the top of the library. Bonfire of the Damned comes to mind for an UR damage oriented deck - since is can kill a bunch of mentors while leaving your now 3/3 flyer alone.
Firebrand Archer: just a minor difference between this and Young Pyromancer or Guttersnipe. This trigger off Moxen, etc, too. So it can deal a bunch of damage in decks with Paradoxical Outcome for example. I don't think it's better than Mentor or even Pyromancer, but it's something to note.