Nice. Looks better than Druid of the Anima or Urborg Elf, but it's also worse than Manaweft Sliver.

Maybe should be a 1/2 or even 2/2 to really justify the rarity hike...

I don't know. I figure you could reprint Leaf Gilder in any set as an uncommon. It always struck me as a strong limited card. Gatherer calls it a 2.55 though. I suppose as long as Llanowar Elves exist, people will always downvote the 2-cost elves.

Yeah, this ability ranges all over the rarity and P/T plot fairly independently. It's at common (Gemhide Sliver, Opaline Unicorn, Axebane Guardian, Scuttlemutt), uncommon (Manaweft Sliver, Alloy Myr) and even rare (Utopia Tree, Beastcaller Savant, Rattleclaw Mystic, and of course Birds of Paradise). The rares and uncommons aren't notably bigger than the commons.