You have to make a lot of sacrifices for lossless editing, so it’ll probably always be a specialized app or at least a separate tool within an all-purpose NLE. For instance, you’re limited to compatible input streams and you can only cut on specific intervals, depending on encoder settings etc.

I guess an NLE could import clips in a locked mode by default that only supports lossless operations, and you’d have to specifically enable the rest. Could be interesting.