There is something that needs to be improved that is not a problem in Bitcoin itself, but in the ecosystem. I think users need safer wallets, so they will not be forced to buy hardware wallets to have a higher level of safety.
But how it will be possible if bitcoin wallets were web base there and there is a posibility of hacking of web wallets .I think it is good to buy hardware wallet as your own investment for securing the safety of your bitcoins. For me it is not the biggest disadvantage of bitcoin.