Personally, I would like to see Magmortar become a better Pokemon. It has a cool design and relatively high attacking stats to complement its large movepool, but its pure fire typing and mediocre speed make it a crappier version of Infernape.
Crustle can't be NU because there currently isn't any such tier in Generation V. Also, Abomasnow is BL in Generation IV and UU in Generation V.
sandslash, marowak, tropius, abomasnow, crustle. Mostly just because i think they look cool and i like the idea behind them.
I bet you could find a use for meganium, the greatest starter pokemon of all time.
Crustle can't be NU because there currently isn't any such tier in Generation V. Also, Abomasnow is BL in Generation IV and UU in Generation V.