To be frank, considering how some other RTwP games that have come out recently have sold (Pillars of Eternity 2), it wouldn't surprise me if the difference between how well that did in the market and how well Divinity Original Sin 2 did on the market that that became a driving force for the motivation to stay as true as possible to TB and D&D 5E rules.
"I used my last magic poo to check in on my daughter." Scanlan Shorthalt.