I tried Shuckle, and won :)) very fun to play, especially with Ingrain stack.
Tried Sable, very interesting to juggle the 3 stats with mean look
Playing Mawile, very nice mechanism to go nomnomnom on the enemy to gain stat :)), if timed well, result in 49x3 = 147 stat through the whole game, quite a reward.
I think Shuckle and Mawile were easy and fun to play (as well as Cacnea and Taillow) with straightforward synergy.
I think Sableeye can be modified as to have item to give a damage boost for having a more balanced base stat (Sum of difference from the average of ATT, SPA, SPD to each of those stats), scaling from 0.8x (unbalanced) to 1.3x (very balanced).
Is there an achievement for successfully Jaw Lock all 49 enemies hahaha.