If by "namecoin v2.0" you mean luke-jr's proposal, that does require a blockchain.




Well, good luck convincing people to use it.  I'm not very interested in spending money or computing power on an entry in a key-value store that could suddenly become frozen due to small outputs suddenly becoming unspendable or some other change to the bitcoin block validation consensus.

Bitcoin works because everybody has a common interest in it being usable as money.  If you're trying to use it for something else you will always be at risk of the majority (who don't care about your weird use) tweaking the rules in a way that breaks it.