Again, I'm not a game dev, but D:OS2 seems grid-based to me, even if it doesn't actually visually display a grid like X-COM: aka - you have a finite amount of moves you can make across a specified area, and each move subtracts from the overall total of moves you can make. This is a grid to me. I presume behind the scenes it's a 'grid'.
Either way, it's a moot point. We're not talking about grids or new skills or anything like that. Just randomisation of enemies.
To simplify matters, they've already balanced each fight around a specific set of enemies that give a specific amount of experience. They could stick with that and just make the enemies appear in different locations (same number, same exp, no balance tweaking needed) and randomly generate some obstacles like barrels. Also, Diablo 2 'champion' type enemies that randomly appear with random stats would be a cool addition as you say, without being a tonne of dev/design work - I don't think any of these additions would spoil the polish, and they'd be great fun in terms of unpredictability.
I get what you're saying, in that they're only human and can only do so much. But it's worth pointing out that a game like X-COM (whether grid-based or whatever) is at its core the same thing as D:OS2, and it throws all caution to the wind re: randomisation, and it works - it works great. I don't see how applying this to D:OS2 would be a million miles away in terms of do-ability. Yeah, it may not be a polished, finely tuned masterpiece - but it'd still be a lot of fun, and worth it as an option after completing the main game. I'm not saying a new game+ should be just enemy randomisation, but I am using the post-endgame as an excuse to offer options that transform the original experience into something cool and different and risky. As I say, X-COM pulled this off - no reason the folks at larian couldn't do the same...
