I never really played the first two when they first came out. I tried to play them a few years ago for the first time, but not being a fan of that type of gameplay, and the fact they were so dated, I couldn't get into them and just played PnP some more. So, I don't want to comment too much on the differences between 3 and the other two. I will say, that I don't think its necessarily bad that BG3 is turn-based. After all, the first two games came out so long ago, BG3 is not exactly a 'natural progression' in the series. Its more like a reboot. I'm also not a game developer so I don't know how well the rest of the elements in BG3 would mesh if they made it exactly like the originals.

However, I agree that some elements in BG3's gameplay is wonky, and you're right that there is not a sense of epicness. I too think a little too much emphasis is placed on environmental factors. And if the strategy part of that was working perfectly as intended, that would be just fine, as that a very important tactical element to any kind of "real battle" which is knowing ones environment. But at the end of the day, this is DnD, not some kind of Ghost Recon game or RL tactical simulator. And anybody that's played PnP knows that sometimes you can just bullrush a battle, get a handful of lucky dice rolls and massacre the opposition, or lose a battle you should have won because of said rolls. What I am driving at is that DnD is not all about placing your miniatures perfectly on the grid(if you use them, which I don't because I hate it) and having an expectation that perfect tactics, or perfect cheese tactics will be the only way to win any encounter no matter how big or small.