As far as an All Evil Party goes....
All my Party are Human/Tiefling. With a Lawfull Evil allignment. Well with one exception.. My Pal is Aasimar,couldn`t really get around that one.
Seems to all be going well. I really don`t see this penalty about using Tiefling characters,and them leveling up slower. I am about halfway through the Ice palace,and my characters are level 9 almost level 10. Of course I kill every single critter in each area. And when I find area`s like where your Air ship crashes... I stand there killing beatles forever... to rack up EX.
Wich makes me wonder.... if Tiefling,and Aasimar characters level up 1 level for every 2 a normal human would...(did I get that right?) Then my characters would already be level 18 or so??? Dosn`t sound right.
Anyway... Evil works just fine! Of course I don`t wipe out the villages,as much as I sometimes feel like it....