Well for one I think you should make another thread if you wanna talk about gameplay sliders.
Anyway, I think that WR catching affects the CPU QB's trust in his guys. I see so many more deep shots with it at 55 than at 50. Costs me realistic drop numbers, especially since they seem to have tuned the drops a bit, but that's a small price to pay.
I also think that the tackle slider affects pursuit, block shedding, as well as CPU RB ability and use of special moves.