I got my internets back, but also developed a mild infection, and couldn't stop playing Monster Tale. So I've finished it now.
It's difficult to say how balanced or unbalanced the monster skills are. Certainly there were only a VERY small number that I ever used. I don't know if they were really overpowered or if it's just a playstyle thing. Most of Chomp's attacks just didn't seem worth it, but it may have been different for other people who naturally gravitate to different styles? I don't know. I was pretty much using nothing but a vertical spike until I got the extremely awesome drill power, and then it was that and Healing until the end of the game.
Still, Monster Tale is great and if you have a DS you should play it. :) Heck, it's currently listed stupidly cheap, buy it even if you don't have a DS and you'll find one or someone to give it to eventually!