II was an easy game, and I actually found III to be much more difficult. I think the problem people have with II is that they don't specialize their characters. Because stats go down as well as up in this game, it is important to make sure your characters aren't nerfed from being spread too thin.
I made Maria my sole caster... She took care of buffs, debuffs, healing, and magic damage... She was always casting magic so her magic power, MP, and spell levels kept up with the pace without the need to grind... Everyone else I just made into pure fighters :P Strength, HP, weapon levels... The Emperor was cake.