. . .I don't think that traditional RPGs need to be balanced like other kind of games . . .
With respect, sir or ma'am, this is totally wrong.
I can't emphasize the wrongness enough. Or the respect. (I don't mean to insult.)
First, let me say what I think you mean -- that way, if I've got you wrong, you can correct me. You're saying that traditional RPGs don't have to worry too much about the relative power levels of characters within the same party. That is, variations of power between PCs is not a large concern in a traditional RPG, you are saying.*
That is way, way off.
*Again, feel free to correct me if that's not what you're saying; I don't want to strawman or misunderstand.
The entire point of a point-buy system is to prevent intra-PC power disparity. And the point of a class system is to
rigidly enforce intra-PC power equivalence! Class-based systems are even more hardcore about this concept than point-buy systems. When you see people talking about "party roles," this is part of the concept they're addressing. Assume, for a moment, that party roles are a concept that should be preserved. If you have a PC that encompasses multiple party roles and a PC that only has one, or has his roles trumped by that other PC, then the first PC gets more screentime than the second. That's unfair to the second player; he has less opportunity to do meaningful stuff in the game. (Note the word "meaningful" there, as in plot-relevant.)
Point-buy systems kick these problems to the GM and other players to handle directly while putting costs on game assets that, ideally, prevent role unfairness. Class-based systems take the problem from the GM and players both and simply restrict what you can play, enforcing the roles in the mechanics. This can be good for quickly making characters (unless your design is fucked -- see also d20) and for reducing role overlap (unless your design is fucked -- see also d20) at the expense of player -- and actually some GM -- liberty.
So, yeah, this is the most important thing in RPG economics. It determines how you're setting up character creation. A traditional RPG is very much concerned about the relative power level of its PCs.
Indeed, I can only think of two, possibly three, exceptions to this concern, and both mildly challenge the traditional RPG category:
1) Toon. The point of the game is to make people laugh. If your character has three times the points of another PC, your obligation is the same. Indeed, being more powerful can be
worse than being weak because failure is funny.
2) Paranoia. Pretty much the same issues as Toon, though less egregious. Still, that game does respect some notion of play balance; its loose design may be just a function of the fact that the designers can get away with it. So what if you're mutant powers are better than his? You're gonna die every five minutes anyway, and the other PCs will just shoot you more often out of fear of your abilities. That's not nearly as bad as --
3) Ars Magica. One PC is the mage. She is ubar. She has tons of powers. The other PCs are grogs. They no do magic. They suck. They're expendable. Every adventure, players switch roles such that everyone gets a turn at being the mage. Nifty idea, though in practice, who could reliably get game sessions that make sure everyone has a fair turn? In any event, this was a selling point of the book because the idea was so novel, and is still so amazingly rare.
So intra-party PC power is hella important, and rarely dismissed in design as a result.
Also, I don't think that's really a concern when it comes to magic items/racial powers (what a Background system would cover). Most of the power disparity in d20 is due to class disparities, not gear and race disparities, and I don't think this new system would make things worse on that front.