Gaius wasn't weak. In terms of pure PvE mechanics, sure - but in terms of his ability to fight he held up pretty well in terms of pure story. We need to remember that the Warrior of Light is surrounded by a ridiculous amount of plot armour, as are many of his allies. So, naturally, a consequence of that is certain antagonists end up getting shafted. For 4.0, though, it appears as though the antagonists will be given more build up and focus which will hopefully translate into them being shown to be both competent and deadly.