Shameless steal from other thread.  Here is my proposal.  Though its not really custom content, just same content under custom circumstances.  
Stat Changes:
- No stat caps
- Str: % damage to each swing.  79 str = 79% dmg output.  270 str = 270% dmg a swing
- Dex: Modified hit rate.
- Sta: No longer affects HP.  Increases improve your mitigation.
- Agi: Improves your avoidance.
- Wis: Mana Pool.  Healing Power (HoTs included).
- Int: Mana regen (% based). Nuke\Dot power.  Pet Power.
- Cha: Spell Resist rate.
Class changes:
- Warrior: Aggro is no longer weapon damage + damage bonus; but, actual damage.  (Change for everyone but affects warriors significantly).
- Shaman: Loses slow.  Loses direct heals.  Gains an appropriate torpor line at old heal spell levels.  Loses regen.  Canni turned into a spell line, takes shaman HP to burst heal target for 1:1 ratio.
- Druid: Gets clarity line. Loses regen.  Gains lower tier torpor line.
- Enchanter: Loses clarity, haste and slow.
- Cleric: Loses HoTs.
- Bard: loses slow.
To compensate, Mob HP be doubled to tripled.  Some status debuffs no longer have X hate.  Poison procs/spells no longer have 400 hate, but scaling hate based off of potency of proc/spell.  Stuns are still high hate but scale off of duration of stun.