Okay, I've been designing a game recently and early on it was decided that it should be classless and levelless.
Someone brought up the concern of some characters being *overwhelmingly* incompetent in fields they didn't deem important at character creation.
There were pretty much a couple of solutions to this.
1) The cost of an advantage could progress exponentially (distributing smaller bonuses in lots of things is encouraged, as opposed to dumping everything in one place).
2) A percent limit on how many of your total character points could be spent on one thing (again, there's a limit on *how* far competency can vary)
3) Dice pools (a pretty easy way of making it so there's a "maximum" of difficulty in any task... progressing dice means you can increase your likelihood of hitting the max, without actually increasing your max).
Likewise, we have an "Adventure Points" resource, wherein a critical success (a success on x-number of dice, where x is one more than normally even rolled, so "you do what you're best at"... long story) gives you adventure points. This means that any character with a high enough ability score to automatically succeed at something would be broken. Hence, we knew our minimum and maximum in terms of abilities.
Likewise, on analysis of the affects of adding one more die... it generally doubled the likelihood of success. So we pretty much had to use the exponential dice-price and the percent limit (one fifth of your total on any one ability) anyway.
And so on and so forth...