I was thinking that it would be really fascinating to create special enhancement trees that are born from specific multiclass combinations. I know that the new enhancement pass makes multiclassing already powerful, but this suggestion is different.
This is best explained by example: Imagine that if a character has six levels of druid and wizard, and takes the Pale Master vampire form, he or she can then access a special Werewolf enhancement tree that would feature DR/silver, fast regeneration, etc. (Currently, one cannot be both in wolf form and the pale master shroud).
I am not familiar enough with the pnp D&D world so I present this here (http://en.wikipedia.org/wiki/List_of_prestige_classes): D&D character prestige list
The Duelist: Duelists are nimble warriors who focus on wits and finesse. They gain a bonus based on intelligence to their armor class when not wearing armor and may strike their opponents with great precision with light weapons. Tree appears with 6 Rogue Assassin and 6 Ranger Tempest
Arcane Trickster: Arcane Tricksters are rogues who combine larceny with magical talent. They may attempt skills such as picking locks or sleight of hand from a distance, and can force sneak attacks even on prepared targets. Arcane Tricksters cannot be lawful. Tree appears with 3 rogue mechanic, 3 bard, 3 archmage: Illusion
Dragon Disciple: Dragon Disciples are those with some draconic heritage who seek to transform into half-dragons. They must have some inherent spellcasting ability to attempt this. Tree appears with Druid 6, Feat: dragonmark, and God-knows-some-other-class.
Horizon Walker: Horizon Walkers are explorer-warriors. They gain knowledge of various terrains with experience, and eventually learn even the terrain of the outer planes. Druid Ranger combo. Ok no one will use this one...
These are just stumbling suggestions.
The player base has already done this by entitling multiclass builds (e.g. the Juggernaut, Cetus, and many more). I am suggesting a way for the developers to formalize certain combinations that would essentially introduce new classes via the enhancement system alone.
Here are more examples are taken from Wikipedia:
Cancer Mage, Lifedrinker, Mortal Hunter, Soul Eater, Ur-Priest, Vermin Lord, Warrior of Darkness, Church Inquisitor, Consecrated Harrier, Contemplative
Divine Oracle, Holy Liberator, Hospitaler, Knight of the Middle Circle, Sacred Exorcist, Sacred Fist,Templar, Justiciar of Taiia, Soldier of Light
Is this idea any good? Any special enhancement lines that you would like to see added that appear from existing combinations?
edit: following Ancient's suggestion, have special trees open also for pure builds.