One thing id disregard in balancing. is the "Infinity engine-isms"
by that i mean gameplay conventions that arose from the games, but not the intnetion of the games.
The classic Baldurs Gate sinlge character Wizard wank. The same is true for divinity with Lone wolf playthroughs.
I personally dont understand what people get from those min maxed single character playthroughs, to me they just seem like more boring versions of what the game is intended to be played like. but i dont need to understand why they do it.
The game should not be balanced around those kinds of players. Theyll find a way to break the game one way or another, so no point changing the XP system to suit such an unusual playstyle.
Beeing able to change the party composition midway through the game and have a good expirience one way another is a superior system to allowing some people to build overpowered characters.
If they want to do that, theyll have a mod that does exactly that on day 1.
Also: man i knew this was gonna happen when they said the level cap wasnt level 10. now the high power level wizard masturbators are coming out of the woodwork now and demand the game is designed entierly aorund their power fantasy, like they do with every single other CRPG on the market.