Turn-based can be damn fun, just play XCOM2.
I agree that turn based-games are fun but XCOM2 may not be the best example. I started to enjoy XCOM2 more after I altered some of the code to reduce the RNG. The game played more like chess rather than just me watching it play without me.
As others have mentioned, the tedium of combat can make the game feel like a drag.
You want turn based without RNG? Play Mutant Year Zero, it had very little of RNG. Its not that fun in the long run. It worked for that game, partly. RNG needs to be there, I estimate DOS2 had 100ish battles. I think Narrator gotta help the player, if you're very unlucky, miss, miss, miss, miss, and enemy just scores critical hits.
What if there was "Wishes" all DD players know what I mean. You could use Wish from Narrator to change thigns around. "Fuck Im screwed, Im gonna use my Wish now".Or you're standing in front of Vendor and theres the item you want, Im gonna "Wish" more money. Hmm, its kinda Cheat Stuff.
Wish brings so much Memories, we used to play tabletop DD with Wishes, all begged stuff from DM.
