Warlord/Assassin...The Variants could warrant this in a high magic world......I feel he should give get bonuses of both....which allows him Specialization of both his crafts .. plus the allotment of Hirelings from both ....a guild of assassins and a Castle.....at start he gets Treasure of both...
People have to make the prerequisites for class whether dual/multi/Gestalts....etc. and other before they go into it for it be to be an option none the less.... There's no way getting out of prerequisites period unless you playing immortal or a God.....