Piling every proof-of-work quorum system in the world into one dataset doesn’t scale.
If you say “no” after you’ve seen how this runs on the test network, I will totally respect that and won’t generate domain registrations on the live network.
Bitcoin is your bird, and if you don’t want it to soar as high as it can, that’s OK.
But even if the domain name stuff is on a separate chain, there is still going to be a Bitcoin transaction for every DNS registration. So having two chains would cause no reduction in the number of Bitcoin transactions, just 40 or 50 bytes reduction in the size of the transactions in the Bitcoin chain.