Krita is one of the best digital painting programs out there (I'd dare say only challenged by CSP).
OpenToonz is professional 2D animation software based on Studio Ghibli's fork of Toonz, currently maintained by Dwango.

Both apps are written in C++ with Qt front-end so the merge should be theoretically possible. I don't know about the licenses however. Krita uses GPL and OpenToonz uses modified BSD license.

Reasons for this proposed merge can be summed up as:
Krita's animation features are nowhere near those of OpenToonz and OpenToonz' painting / drawing features are nowhere near those of Krita therefore even ommiting everything else one software has, that other does not, and only focusing on these main features (painting + animating) both apps have a lot to gain from each other. The merge would probably also result in more fluid workflow (especially for animation).

First step would be for OpenToonz to join the Krita Foundation. By doing this it would probably also benefit in the development coordination because afaik Dwango is "the maintainer" of OpenToonz, but no longer taking an active part in it's development. (* https://github.com/opentoonz/opentoonz/issues/2746 )

Of course it'd be a lot of work. I tried to keep it short.

I'd like to know opinions of both Krita and OpenToonz community members and devs.