Although I personally think type inference is the killer feature that makes static typing accessible (almost always auto), I've seen hostility to it, in particular among C++ and C# programmers. The point of this project, as you say, is to be as explicit as possible in the code, while at the same time presenting a view of the code that is less cluttered.

My initial impression is that if I were to use a system like this, I would want any type annotation that differs from the default inference to be visible. The only choice left, then, is when to display redundant annotations, which is where a lot of the disagreement around type inference is, even without this scheme.