Warlocks rule, since magic is no small thing.
Jeddit is a cool guy: I constantly get earth, air, water, and fire magic. And diplomacy has one of the highest % chances of appearing. Which also rules on some maps.
regarding "too expensive" — good things cost a lot.
regarding "black dragons" — natural resistance to magic sometimes helps; yes, they can't be resurrected, but in this case an artifact might help.
And I won't even mention the mana vortex... you don't have to push knowledge too hard and can instead pump spell power.
But overall, to each their own. Swamp is also pretty fun.