Personally I think that at least two of the points you bring up as being detrimental to contribution are things that make contributions *easier*:
* A strict coding style is the only sensible way forward in any serious project; I may not always agree with the coding style in the projects I contribute to (GNU coding style *shudder*), but I rather have one single style than having total chaos because everyone uses their own style. If you have trouble with the coding style, indent can *probably* help you.
* Being implemented in C makes the code a lot easier to understand -- to me C is pretty much a pre-requisite for me to contribute to a project. C++ is usually a big turnoff (a restrictive use of C++ that some Qt-based software I've seen adhere to is fine by me, but sadly most C++ projects are totally impossible to understand without reading large parts of the code base)