Indeed realtime preview of 3D scene is a powerful feature that you won’t find in a regular NLE.
AE isn’t really an editing software, you can of course edit shots, but it’s more aimed at animation, motion design, compositing…
VSE is a bit similar, it’s better at doing quick edit, image manipulation ect… To have similar features as a true NLE is will be IMO too much work and maybe will loose original focus of the VSE.
IMO there are few “simple” stuff that can already be very useful without touching the core design :
-add more blend mode : you can composite strips using alpha over/under , cross, add , multiply.
adding screen, overlay, soft light, dodge,burn ect… would be awesome.
-add more strips modifiers :
hue/saturation/value , this can help getting all in the same place, you can tweak saturation in the filter panel, but you can’t do hue shift.
maybe blur and glow filter can be ported as a modifier too so everything is in the same place.
A more complex work would be to rework the cache system so it can play realtime easier. But I guess it’s a tough area to tackle.
If not speaking too much, VSE is developed in right way will create a havoc & will drift monster post production tool makers to rethink about their traditional post production application.
Hum, it’s already a bit the case, as a pipeline/review tool it’s already quite good. I’ve used it on many productions, I’ve read that Tangent Animation is also using it quite intensively on their feature films.
To make a regular NLE, it’s too much work I guess, it won’t make too much sense also. If photoshop get a full featured sound editor , would you really use it as a professional ? or would you just use a standard software that isn’t filled with image operations you’ll never use.
To understand better what is needed as a professional editing software :
-it should be able to manage hours of video, store them internally in folders, add tags so you can manage you footages easily.
-it should handle different footages with different framerates , size , being able to de-interlace them and re-interlace them as needed.
-it must have a bridge with color grading application (.EDL,XML) to at some point send the edit for professional grading tool and get it back in the timeline.
-it should display video thought professional card / monitors like this one : https://www.blackmagicdesign.com/products/smartview4k
-Of course it should at least be able to pull a quick greenscreen key to preview VFX in the edit and then send them to the VFX team.
I’m sure a professional editor would see a lot of other issues, all this stuff that would be required to get a true interest from production companies in blender as an NLE.
That doesn’t mean it shouldn’t be improved, but IMO it should be improved in areas it’s already good at.