Switching to real time requires overhaul on encounter basis. Realtime gameplay tends to have more encounters. It would require huge amount of work for modding team.
But why conflate two separate things? Balancing encounters is completely separate from creating a RTwP mod. I would be fine with a mod that just only enables RTwP combat and nothing else. All the talk of how encounters in TB games are "hand crafted" and "unique" and so on are complete nonsense to me. I have yet to see a single combat encounter in a TB game that was in way better designed than such encounters in any RTwP game.
The things are inextricably linked if you want an even a remotely balanced gaming experience. D&D 5e + verticality + environmental interactivity makes for a HUGELY complex system UTTERLY incompatible with real-time combat. Any difficulty that would challenge turn-based combat players - would totally smash someone playing real-time unless a severely dumbed down AI was implemented. You can't ever have played DOS2 for instance if you think generic is as unique as hand-crafted. Two years after playing the game, I can remember the majority of the battles, and the major ones vividly so. I can remember most tactical decisions, from positioning to targeting priorities. I can hardly remember any real-time battle of more recently played games. There simply is no comparison, one is cerebral the other instinctive.
This is just TB-superiority propaganda nonsense. Both WotC and even Larian devs have stated that 5e rules are quite compatible with RTwP even if some elements maybe harder to code. And D:OS combat encounters are among the worst-designed encounters I have ever come across in a videogame They were completely boring, repetitive, and far from challenging. It is the easiest thing in the world to make "tactical" decisions when your enemy is a statue. By definition, a combat situation where you are the only one able to move and act while everyone else is frozen stiff is NOT tactical. One can be tactical ONLY in a dynamic situation (i.e. real time) and never in a static situation (i.e. TB).