ADA updates would be good, bringing in the Spark 2014 and early 2015 extensions would have been nice. (Spark is a mathematically provable dialect of ADA. Well, mostly. Apparently, you can't prove floating point operations yet because nobody knows how. Personally, I think it's as easy as falling off a log table.)
There are also provable dialects of C and it would be nice if GCC had a flag to constrain to that subset. Using multiple compilers is a good way of producing incompatible binaries and nasty interactions. GCC has no business having limitations. :)
With work on KROC at a standstill, we have a reference compiler that talks Occam Pi. Occam is a very nice language to work with but working through archaic Inmos blobs is tiresome and limiting.
Code quality in GCC and GlibC is still poor, the stability of internal interfaces is derisory (these should be generated from abstract descriptions, ensuring the flexibility GCC wants and the usability interface developers want) and the egos of the developers should be taken out and shot. However, it's still one of the best environments out there. Those that are better at specific things are usually carrying three to four digit price tags. I'd write in hand-turned assembly before paying for unquantifiable products that I won't even own.