I will always play a knight in tibia, that is just who I am, it doesn't matter much to me if they are underpowered or overpowered.
I do agree on some kind of balance between the vocations though, for everyone who likes to engage in pvp or for people who prefer to level up the fastest, each vocations weakness and strength - all of this must be fair for all. Vocation balance is an essential part of the game.