Well a few things to address I suppose.
The law system is okay. I don't think it adds that much more to the game, but each bit is nice I suppose. The thing is, they are very specific. So pay careful attention. If it says you can't use "Fight", then that's all. You can still you your Battle Techs or whatever secondary methods of hitting your character has. The law I found to annoy me was Copycat, since you can't use the same ability the person before you used. If I used "fight", the next character after me can't use it or he gets a card. Took me a minute to pick up on how that one worked. The real thing I don't like so much though is the system. I enjoyed the charging of the original FFT. I had to plan in advance with spells and such. I also liked the classes a bit more, they felt less repetative. I also enjoyed the fact that you bought techniques with JP rather then learning from weapons. I have to many weapons I have to keep in my inventory. What I do like better about FFTA however is that I can now see battles on the map. I can avoid them or fight them. It always felt like when I was trying to get somewhere with FFT that a random battle would pop up. I enjoy the fact that there are more races, I just don't enjoy the lack of diversity among the jobs they can do. Aside from that, I don't have much problem with it, it's minor stuff really. Some things I like more, others I don't.
As for the refilling MP each turn, no your mage cannot just run around using his strongest attacks. The amount you recover each turn is barely enough to let you use Fire, let along Fira.