The Wild ARMs games started out with three party members, shouldn't you be happy they went back to their roots? :/
i'm never in favor of a series taking a step backwards unless its a situation like xenosaga 2 -> xenosaga 3. also i think 3 member party's are fine if theres only 3 playable characters. in my opinion it was particularly bad in FF7 since one of the bosses sticks you with a random party effectively punishing you for only focus'ing on a few characters.
Dade i'm not trying to say ffxii should of had ffx's battle system. however had ffxii had ffx's battle system and say removed the tag in/out function thats where i would have a problem