I also would love to see that. My use case is applying a crop filter and then do cutting with that in place.
I don't know what "live editing" should mean, but if you mean filtered output while stopped, there are design limitations and fundamental considerations which resulted in this feature being not offered. The problem is with video filters which modify timing, with video filters which operate on multiple frames at once as well as with very limited and imprecise seek when filter chain is used.
Okay, sounds understandable, even if it would only be for crop.