Well, the battle system is just part of the whole. I like to think all aspects of the game when considering it's worth. A game can be good, if not better, even if it doesn't have a strong emphasis on combat. Me, I'd certainly wish to see games where diplomacy played a bigger role- you could honestly talk your way out of conflict situations by trickery, reason, bribery or intimidation, instead of the usual 'fight-to-the-death' setup where monsters and opposition are there just to make dungeons up out of a mish-mash of corridors, a few odd traps and a chest here and there, and the boss fight at the end. Very unimaginative and boring.
Still, on the subject of battle systems...as long as they work and are not cumbersome or filled with idiotic arbitary restrictions (take the 'red card and you're out' for using swords type of ruleset from Final Fantasy Tactics Advance, for example).