What is one problem with Bitcoin that is going to hold it back?

[becker]

transaction times.

[cafucafucafu]

All other issues can be overcome except incentive. There is no incentive to have it for the masses.

Unless somehow the incentive magically appears BTC will slowly die away as miners switch off.

[gkv9]

The worst scenario will be, when your PrivKey gets compromised and exploited without any reason... I had my friend who lost more than BTC5 which he had in his Blockchain.info wallet, as it was hacked... Not only limited to that, but there are websites where some PrivKeys are leaked to prove that its completely wrong that it is almost impossible to generate a key-pair identical to somebody else’s...

[inBitweTrust]

1. Loss of net neutrality. I would divest 50% if this happened. It could mean the end of free, unfettered use of BTC.

I don't see how this has anything to do with Bitcoin. If you are referring to filtering and deep packet inspection than those concerns are unwarranted because getting around them would be trivial. Additionally, with projects like this - https://mycelium.com/bitcoincard their restrictions can be bypassed easily.