I like magic-heavy parties. I'll use a knight or a barbarian (and I mean "a" - one only) in 6-man parties like you have for MM3-MM5, but I tend not to use them in the 4 & 5-man parties of MM6-MM8. My favourite party for MM8 starts with either a necromancer or a cleric, and I end up with a necromancer, a priest, a vampire, a dark elf (Cauri), and a dragon - so I have a party that has access to all the spellcasting abilities and all the magical monster powers. I don't start with a dark elf because you can get Cauri Blackthorne into your party so quickly. I then pick up the other players available in Blood Drop, get through to the mainland, and make my way along the coast to Garrotte Gorge as quickly as possible - going that way avoids most of the hostile monsters. I can then get up to the dragon cave to swap Simon Templar for Ithilgore, the young dragon. My only other voluntary player change is that as soon as I unstone Cauri, I'll swap either Devlin Arcanus or Frederick Talimere for her, depending on whether I started with a necromancer or a priest. You've got to take Overdune Snapfinger and Dyson Leland into your party temporarily for quest purposes, but I get rid of both of them as soon as I possibly can. I dislike Dyson, he's a whingeing misery.
A French gamer called Ice (IIRC) created two starting positions where your player character was a dragon. I've played games with both, but the Dragon is a very powerful character and again, the games tended to be too easy.