I know that there is no cell respawn (if you clear out one spot, that's it, no more enemies there), however, why not add roaming enemies that respawn randomly from 1 day to 3 days (to prevent XP farming)
You add mobs of enemies that patrol the map.
That way you can still be surprised after going through a cleared area and you wouldn't have stationary cell respawn which would allow XP farming.
I'm in the process of studying the mod tools for the engine but with the university breathing down my neck who knows when that could happen.
Would be real nice to consider my proposal or at least point out the flaws.
For how game works roaming enemies probably clutter the map way too much and may cause save game bloat. And this isnt a farming game like diablo but im very confused by their randomised stats choice.
Instead why not do it like Tyranny, when you fast travel there is a chance of random encounter which may or may not result in fights, gold, chests or story events, which spice up things abit.
Dont think stuff like this will ever happen officically so wait until mods.