The actual numerical value of the starting level is irrelevant. At the end of Divine Divinity your character is (generally) pretty much untouchable, with only a couple of the end bosses a possible threat. IMO it would be a little lame to simply drop the Divine One's abilities until he just happens to be a match for the most common generic opponents at the start of Divinity 3. That wouldn't really bother me (character resets being a long tradition in RPG sequels), but from a design perspective I think it would be better to play a different character.
