Nerf Suicide Squad, change Stasis ward to be less silly, remove either of his mine skills and replace it with something useful, change the other to fit most needs of both. Not saying that isn't fundamentally changing everything about him, but I think he should still be slightly closer to something like Engineer of HoN where the mines aren't everything. I doubt the 3 invisible mines thing would transition that well into Dota 2, especially when there's less time at the beginning of a game to go place mines and they probably aren't changing that for just one hero.
And they could just make Camouflage passive on self and Treant would be 100x more fun hero to play.
Edit: Also, according to Purge Skywrath is being remodeled so BB might be next.