> There's nothing like After Effects for example - Blender can be shoehorned into that role and is actually (technically) very good at it but it's a million miles away from AE in terms of usability.
Are you aware of Natron, Lumiera, Vapoursynth?
I know a startup that has a production pipeline built around AE but they're using some specific functionality and don't come from a Linux background at all.
Well, I don't think so. This may work for small tools but not for bigger software projects. Nowadays an application is useless if the source code is not maintainable.
Technical details: Some years ago I've been the maintainer of a program that has been developed by two "software engineers" (who both left the company without writing a documentation) within six years. No one except the customer knew all features. GUI app, C#, .NET 2.0, about 100k LOC within 20 "classes". No separation of concerns, no dependency injection (and of course no unit tests). Missing or wrong inline documentation, misleading names....so yeah, like playing minesweeper. If you are willing to improve yourself start here: http://lumiera.org/project/background/CleanCodeDevelopment.html
There is also an attempted rewrite of Cinelerra as a new program called Lumiera.
But it's been developed for 4 years now and they are still in early stages, although it seems that they are still active.