I recently posted a couple of suggestions on uservoice that would save me from some future maintenance nightmares and improve the performance and memory usage of BEPUphysics in the long term.

First, it would be really nice to have wide support for unsafe code so that I wouldn't have to maintain a bunch of separate code paths. One of the primary targets of BEPUphysics, Windows Phone, does not currently support it. It would be nice if it did! If you'd like to help, vote and share this suggestion:
http://wpdev.uservoice.com/forums/110705-dev-platform/suggestions/4715894-allow-unsafe-code

Second, generic pointers in C# would make dealing with low level memory management more modularizable and much less painful. I could do all sorts of fun optimizations in BEPUphysics without totally forking the codebase! Here's the related suggestion:
http://visualstudio.uservoice.com/forums/121579-visual-studio/suggestions/4716089-unmanaged-generic-type-constraint-generic-pointe

And, as always, if you want to see the above notifications and others in a slightly less readable format, there's my twitter account.