Given the way Design and Development have gone recently, there's one thing I'm sure of, and its that whatever the mythic Entomb card is, it will be very pushed. Is it going to be standard-pushed or eternal-pushed? Who knows. But if they go for a utility creature rather than a midrange value beater, we could have a sweet vintage card on our hands. Again, recent design trends tells us it will a midrange value beater, but they've made statements recently that suggest they have learned from recent mistakes and might swap things up. If we get something like a 1-2drop that exiles all graveyards when it ETBs (and when token ETBs), or has a tax effect, or stops non-drawstep draws, then we're in business, and that doesn't seem completely out of the realm of possibility to me.
edit: welp mobile definitely caused me some trouble there, sorry for the deleted duplicate below