Imho the tiers need just to be split in versatility (ability wise) and combat power.

The regular tier system does a good job when comparing the versatile power of classes/builds. But it doesn't say much about the combat power.

Think about uberchargers. All builds fall into T3 or T4 and you can't say much about the builds with telling the tier they are in.
We need give the builds points for combat power in terms of:
- dmg per single attack
- dmg per round
- how well can the dmg be applied (is there enough mobility)
- defenses: how easy or hard can you be shut down (SuckOrSave spells/effects, ambushes, vision depandent...?)

we need Combat Power lvls and definition for it imho.