Upgradeable ram would be the only thing I’d want from Apple. With the advent of Dropbox & similar it’s been a long long time since I’ve run out of disk space. And as I’ve said before, I typically see laptops struggling to perform long before seeing their batteries give up on me.
All LiIon batteries are around 80-85% of capacity in around 350-500 charge cycles given a decent controller and no excessive heat (which macbooks are overall bad at).