I'd like to see the ability to have separate "accounts" where I could set aside money and keep track of it separate from my "pool" of money. Like you could have a car maintenance account where you put 0.1 BTC a month and then paid for oil changes, wiper blades and car washes from that "wallet." Or you could have a vacation savings account, emergency fund, fun money etc..
I've wondered why regular banks don't do this. Probably because it would encourage people to save and budget instead of using a credit card.
I use
mvelopes.com to do this with my bank accounts since the banks don't offer it directly. It would be nice to have this for my bitcoin.