I agree as well; while the overall principles are easy ("roll d20 + modifiers, you want a high number"), character creation complexity is where games usually get players in terms of complexity(/decision paralysis). 6-8 players with one DM/GM who knows the rules makes for a difficult time at character creation. Especially if you using more than core rules for some reason.
Character creation with new players in a complex long running game is usually at least a 2 week process of conversations and email exchanges. As such, a complex rule set may be entirely unsuited to a pickup game. Of course, a system like HERO, GURPS, M&M or even 3e D&D - whatever their positive merits - maybe completely unsuited to a pickup game even with experienced players, as character creation might well take 3-4 hours even then.
Character creation takes alot of planning, and probably should not be put off to the kick off game night.
The only real solution to this is to use pregenerated characters, but this may not be fully satisfying to everyone as one of the joys of a game is playing the character you want to play.
For this reason, 'rules light' games may be better choices if you want to do a spontaneous short session. Even a game as complex as oD&D or BECMI may not be simple enough to allow for a quick pickup game with new players. Character creation may still take 3-4 hours by the time the DM gets to everyone's character and guides everyone through the process. This is a recipe for alot of boredom.
In short, if a new players introduction to a game is through a 'character making session', then, yes, I do agree that this can be daunting, confusing, and sufficiently unfun as to turn off a new player. Stacks of books, confusing jargon, and a vast array of choices is not the way to go about winning a person over to the hobby. It's far better to get the player's ideas about what they want to play: 'a vampire hunter', 'a dinosaur rider', 'a magician that blows things up', etc. and guide them to what they need from the rules to achieve their goals rather than hand them a stack of books. That process is going to take alot of time, most of it just talking, and its far better IME to spend that time conceptually than in complex rules discussions.