are you still trying to duplicate NameCoin on bitcoin?
OP_RETURN could be used for the domain name, and create a DNS on the blockchain.
bitcoin is a currency and a payment system, it should not be used for things that are not related to that. in fact OP_RETURN should not have even been added to bitcoin in first place.
but yes you can do that. here is a cool project running a website without host, DNS,... and purely decentralized using OP_RETURN data on bitcoin network
https://github.com/elendirx/web2web