I think the only thing I'd want to consider really changing is the mining. I really miss the days of CPU/GPU mining bitcoin. It would be nice to see more coins come back with CPU/GPU PoW algorithms, avoiding presales, premines, and the centralisation that comes with them. I don't hate ASIC mining, I just find that their prices are utterly insane and the noise in addition is just too much for any regular folk to have sitting around.