Please note that we've updated the Mount & Blade II: Bannerlord save file system which requires you to take certain steps in order for your save files to be compatible with e1.7.1 and any later updates. You can find the instructions here.
Would be great visually but this engine doesn't seem to have good particle effects so I assume they would have to improve leaps and bounds in that department before anything like this would happen. Also particle effects shouldn't clip through units which is a bit rough when you are talking about potential 1000 units but I guess this could be limited to only a certain number of units within a few meters. Anyway would be nice but I doubt it will happen, that is a lot of work.