Well, I've played several turn-based games, and I generally like them. Solasta, when it came out was the best, but the travel options and rest mode could have been better.
BG3 hit a home run with their camp scenario. That was pure genius.
One of the other shortcomings of Solasta was the limited battleground area setup. BG3 is much better, and I like that you can make camp anywhere, because that is reality. You are adventurers out in the wilderness, so you should be able to make a fire and drop your bedroll almost anywhere.
I like how BG3 has used the 5E rules, although I didn't really play 5E (I was long before that time) and I actually learned about 5E watching Critical Role.
I don't think BG3 will replace anything, as I still enjoy the Assassins Creed combat, still like Skyrim and the Witcher to this day, but the old D & D, turn-based combat, I love, and doing it on PC with the visuals is a Dungeon Master's dream.
Now I have played Divinity, but I'm here to tell you BG3 has that totally outclassed.
If someone gave me money to disagree with this comment, I still wouldn't be able to disagree more than I already do.
EDIT - Since I'm not on my phone anymore I guess I can elaborate a bit.
- For a start, I was very pleased with the way Solasta handled fast travel options. It wasn't just better than BG3 "by contrast", it was actively one of the best systems I've seen in the genre.
- I ACTIVELY DISLIKE the camping system in BG3. It's extremely resource intensive AND unnecessarily immersion-breaking at the same time, as it creates a massively artificial disconnect between what you are doing during your exploration/adventuring and what you do in camp, and while Solasta's solution wouldn't be my first pick (that award would go to Kingmaker/Wrath of the Righteous, that allow for camping almost anywhere given the right conditions, but at a price) I still find it far more a far more convincing (and economical) design choice. Permitting camp in few areas "suited for the task" contextually to the game world or as part of the travel time was simple and elegant.
- I have no idea of what you EXACTLY mean with "battleground area setup", but if we are talking about environment I can tell you that Solasta has actual verticality in its scenarios. Flying things actually fly rather than floating two inches from the ground, wall climbing is an actual thing characters and monster can do, you can set "ready actions" and so on.
- While I still rate the overall BG3 experience fairly high compared to other titles in the genre (and it's probably the current king of said genre strictly in terms of production value), almost every single thing BG3 changed from the core rules of 5th Edition was NOT a change for the better, so I'm not exactly willing to praise that aspect, either.
- I also don't like Assassin's Creed (one of my LEAST liked popular franchises, in fact) nor I rate particularly highly Skyrim, so there's that as a bonus.
I do agree that BG3 outclasses the two D:OS games easily, though. Which on the other hand as a praise has a vein of irony in it, since a large part of the improvements that make it better come from the fact that it isn't built on their own proprietary ruleset and setting anymore.