Why is this important? If this new coin is sooo superior, exchange your Bitcoin holdings into this new coin and forget Bitcoin.
It's important because once such superior currency is introduced and becomes known, the selling pressure on Bitcoin will make it such that the Bitcoin holdings will become worthless faster than it can be exchanged for the new currency - unless one foresees the outcome way before others do (which is why I'd like to be involved in these sorts of discussions now).
All upcoming bitcoin vulnerabilities or other unforeseen issues will be fixed as the bitcoin devs want to maintain their wealth.
If Bitcoin technology is such that it can be fixed over time (which goes back to my original question), then that's great - exactly what I wanted to hear.
It's a fully open source project. As things happen, people will fix them. Other than the transaction records, it would seem to me that practically everything about it could be changed if necessary and desirable. It is, after all, a consensus based protocol.
EDIT: Pulled the trigger too fast
As to a superiour currency coming out, well, that's more external than the strengths or weaknesses of the protocol. It's more about getting the currency widely accepted. To my mind, THAT is the biggest weakness of Bitcoin right now. It's still "geek currency". Being a geek, that's cool with me as far as it goes, but for it to retain value, or even gain, it must become "every man's currency". Contrary to some of the nuttier advocates, I don't see it beating out fiat currency. (as desirable as that is). However, it works very well as an adjunct and an alternative. In the physical world, you have cash as an irreversible and easily exchanged anonymous currency. In the digital world, you have bitcoin and it's derivatives. (Yes, I understand that the transaction record is not 100% anonymous, but it's close enough to be viable, if you are cautious).
I would like to see bitcoin payment available at Wal mart. When that happens, Bitcoin has gone mainstream and any issues with the protocol will be sorted quickly.