The reason why there is no best build is because different people have different focus. For example, if one consider tanking to be the most important, then full str blader or warrior would be the best build. If one consider damage to be the most important, then full int chinese nuker and wizard will be the best build. If one want to support his allies, then cleric would be the best build. The rest are all in between.
Full Str Glavie is currently the most balanced character in the game atm. Due to being so balanced it happens to be one of the best characters. A Euro counterpart to Full Str Glavie's are Full Str 2H Sword/Dual Axe Cleric. I base my forms of balance as... Range, Defense, Damage and Teamplay ability. Obviously you won't find Rogues to be the best because they don't have good Teamplay ability or Defense. You also won't find Bladers that good, fighting vs. Holy Word/Spell, due to their lack of damage.
Having a good balance of abilities allows characters to be better than others. Without this balances the PvP, and even PvE at times, are extremely dificult to play in normally.