The current page already shows in both USD and ETH regardless of being premium period and I think it’s better to keep showing USD premium amount (as well as ETH) so that it’s easier to see how much premium it currently has relatively to the base price (which is $5~ denominated in USD)
Showing in $ENS only makes sense to me if you are proposing to charge in $ENS which is a whole separate discussion topic discussed at ENS Registration Fees.