This flaw is in regards to classes. Always there seemed to be a need to have either four (or less) rigid class concepts, of a bazillion different classes, sub-classes, kits, prestige classes and the like in games. Often many of the different classes were really identical except for the addition of a term like "shadow" or "death".
For Piecemeal I created the "Pie Piece" system. Assuming one did not take some trait (more on that later) that altered it, characters receive three "pie pieces" to build their character class.
There are 5 different types of pie the characters can choose from. I'll go into the exact definitions later, but they are listed below:
Warrior: Anyone who's power comes from physical combat
Thief: Anyone who's power comes from stealth
Wizard: Anyone who masters their own magical forces
Priest: Anyone who gets their power from a deity
Bard: Anyone who's power comes from speech and other people
The more "pie pieces" a character puts into a class the more skill he has in that field. Having a single piece only gives you the vaguest abilities, and should only be taken (mechanically) if you can use those abilities to supplement those of another class. Having two "pie pieces" in a class makes you more or less able to stand on your own in the class. Having three "pie pieces" gives you that extra kick to make you truly excel in that one particular field.
This gives new characters alot of different options for how they can be trained. A paladin could be portrayed as a "2 part warrior 1 part priest", a gladiator as "3 part warrior" while a courtisan spy might be "1 part thief 2 part bard".
What about something really out there, like a ninja? A ninja would be a "2 part warrior 2 part thief". How is that possible? Some of the starting traits alter the number of starting pie pieces in exchange for another benefit or flaw. In this case "elite training" would allow a character to start with 4 pie pieces.
What about truly epic characters? like a Kensei?
Part of the advancement process means that when a character becomes "world class" he gets to choose another pie piece. This also allows him to put 4 in spot, unlocking what you would call "epic specialists".
This a Kensei could be a "4 part warrior", an Archmage a "4 part wizard".