That wouldnt be a 'perfect' character, it'd be a 'god mode' character.
Very true.
Personally for myself a 'perfect' character is one I have a lot of fun with, even if or especially when they have areas that they're absolutely naff in, as trying to work round the areas that the character isn't much good in can provide a good challenge.
I think that what a lot of people see as a perfect character is mainly due to your steriotypical Adventure game, where the game is designed around the central characters strengths and they also usually ignore the characters weaknesses or at least downplay them in order to provide a game which is more fun for the user.
RPG's and cRPG's on the other hand are designed around a story, which lets us choose who the central character is going to be, which means that we can pick characters who are out and out Combat Wombats (pure combat machines so to speak), Sneaky characters, Cerebral characters (whether it's a mage or a scientist of something similar fitting to the story), Diplomats (Characters who specialise in talking their way in or out of situations). All of which mean that there will be situations that suit one or other of the aforementioned character types more than the others in the game, mainly as if the game was all combat it make trying to complete it with some of the character type choices harder than others likewise if the game was all about making deals and talking your way through the encounters/events in the game.
Any 'good' RPG/cRPG worth it's salt will be set up so that each of the concievable character types that can be chosen or made is catered for throughout the game, but there will also be some situations where it will be harder for one of the type than another, which I think is part and parcel of the game.
Basically what I'm trying to say is that a 'perfect' character at least depending on the game doesn't have to be one who is a master at everything and that you can have just as much fun if not more playing a character who is at a decided disadvantage in some situations due to their speciality being focused elsewhere.