I'm running a houserule in my game to help me design NPCs, however my players just hit level 5 and any rules I use for NPC I leave open for them. So, could any of my players potentially destroy the campaign world with this rule in place or does this rule require any revision. As I'm sure you all know in E6 you stop leveling at level 6, then every 5,000 experience you gain a bonus feat.
Houserule: When you gain 5,000 you can either: gain a bonus feat or gain a level in a prestige class, overwriting your last level in a non-prestige class.
Example:
A Rogue 4/Fighter 2 has BAB +5 and qualifies for
Anointed Knight so he gets 5,000 experience and trades in 1 level of fighter or rogue, for 1 level of Anointed Knight.
Now if he trades in a level of rogue, it's his 4th, so he'd lose uncanny dodge, HD would go up from d6 to d8, would lose some skill points. His BaB would drop but then be put back up, so he would still qualify for anointed knight.
If he trades in a level of fighter, he loses a feat, his HD worsens from d10 to d8, he gains skill points, Same issue with BaB.
Player can trade from any base class he has, loses the highest level.
A player could become, for example, an Assassin 6. A player could become an Archmage 6, but would lose all spellcasting (Archmage requires an existing) but a Wizard 1/Archmage 5 would work. (just an example, I don't think you can get 15 ranks in a skill in E6, even with the skillpoint/rank increasing feats.)
Now, I would let a player do this, but if they lose a requirement for the PrC then they lose the benefits for the PrC. So say their BaB dropped to the point where they no longer meet the requirements, they lose the benefits, if however they do this again or get a feat/item down the line that re-qualifies them, they regain the class features.
So, are there any builds that utterly break my houserule?
I'm thinking of dropping a Factotum 3 / Chameleon 3 into the world, getting 3rd level spells is certainly not a bad thing.
Oh and before anyone says Urpriest, only 3rd level spells/spellslots exist. 4th level spells or higher are only obtainable via Ritual or Incantation. So whilst a Factotum 1/Chameleon 5 would technically get 4th level spells... it doesn't work because of the way magic worlds in the campaign world.
The intent of this houserule is to have unique and flavourful characters... I'm just curious if there's anything that becomes completely broken for E6. Maybe Hellfire Warlock.... might go research that.