This is all going to depend on how much you enjoyed the original release. If its a game you've said to yourself or know you wouldn't mind playing it again, then maybe the lower price point is enough to bite. The game does look noticeably better in areas. Smoother framerate, higher resolution models, higher native resolution, and better hair... its a cheap price at half off, but you just KNOW it'll be lower in a few months time.
If you haven't played it - then yes, for this discounted price - very much so. But since you HAVE, then BIG FAT NO. And if you think about it, if you'd really strip it out of those numerous collectibles, there isn't that much of a game to begin with, even if I REALLY LIKED IT FOR WHAT IT WAS...
I can't really answer for you since I didn't play Tomb Raider last gen. However, I can say that if you didn't play Tomb Raider last generation, absolutely get the game. I hadn't played it and loved the game, probably my favorite title this gen so far next to Infamous.
I bought it a few weeks ago before these price drops (ughhhh), but so far its been pretty good. I haven't finished it yet cause I've been working like 50 hour weeks but im gonna try to get it done this Sunday. I would only buy it if you haven't played it before like me. I will say however though that the game looks fantastic on ps4 and im loving the 60 FPS. Its so smooth.