If you have enough knowledge in C/C++ you could contribute to the development as well.
I can indeed contribute, but this doesn't matter if my code doesn't get approved. My code may be good enough for the Bitcoin community but it may harm the developers' interest. Look at the block size!
Those decisions (block size) aren't taken simply like that . See here : https://medium.com/@bitcoinroundtable/bitcoin-roundtable-consensus-266d475a61ff
Blocksize should be 2mb next year as far as I know (if they have enough support) , I'm not sure what kind of support though. since they said "community support"