Well, it certainly will need its own .dll dependencies if you guys are wondering, as apart from the editor itself, things like static meshes and particle systems are built natively and thus depend on the same things, just like Dr.Flay pointed out.
However, in my own case at least, it doesn't really matter as my next thing will have its own .dlls itself, so this comes right on time for me, and if it delivers what it promises to deliver, and considering UEd2.1 already which was already something close to a positive quantum leap in technology UEngine1-wise, it will save me several months of work and increase the overall quality of the thing I am going to (try to) build.
Furthermore, even with custom .dlls, that's why NPLoader exists.
So bring it on, once it gets released I will probably try it right away.