Lookout is a very powerful card and it's also great. It's not better than Ambassador, but it's one of the strongest $3 trashers for sure.
I'm not too sure about this. Steward, Masquerade, Amulet, and Ambassador are certainly better, and Forager, Hermit, and Doctor are about the same power level as Lookout, in my opinion.
The point is that trashing is that powerful. Lookout is mediocre compared to other trashers, but it's still very good overall. Develop is a weak trasher, but trashing (and also the TfB effect) make it decent overall.
On this board, Counterfeit is probably the stronger trasher, but it competes with other key $5 cards and Lookout works just fine.
(Edit: Uh, I guess that wasn't Awaclus' point after all. I like Lookout, but I wouldn't put it on part with Steward, heh.)