There are hundreds of race/class/specialty/cabal/subcabal combos, but how many of them get played? A dozen? two dozen? In my personal opinion, its gotten to the point where if you aren't rolling a power combo its challenging to even be competitive. That's because half the combos aren't viable, and some of the combos are just ridiculously powerful.
So I propose a fairly simple system, wherein each Class, Race, Cabal, and Subcabal, as well as the interaction between each of these is essentially assigned a viability score.
Every combo starts at some baseline, let's say 100.
Each time a PK happens, the viability score of that combo drops very slightly. Each time a combo is PKd, the viability of that combo increases.
We tie the viability score into the underlying probability (roll) system of the mud, at a deep level. If Ogre Warriors are trashing FL, every successful one causes their viability score to drop, until all of a sudden ogre warriors are an underpowered combo. Over time, they rise back up. If faerie warriors are all failing they will slowly rise and become more and more powerful. The combos that are all successful all become weaker automatically, and the unplayed or constantly dominated combos become more powerful automatically. It would be slow enough that no one character is shaking the balance, but at a high level enough contribute so the combo gets "auto-balanced". Combos that are repeatedly rolling the pbase will fall down to a point where they aren't anymore.
This would have to tie into underlying rolls for damage, saves against spells, defenses, losing concentration, etc.