Eldraine could return in a future, but I guess it will be in the same year than a new set of cards. I see a great potential as space to create and tell new stories. We shouldn't be totally surprised if some day a cartoon serie set in Eldraine is produced.
About Itxalan it sounded like an one-shot. It may be a fabulous setting, but the failure is the morrion (the helmet used by the troops of Spanish empire) is too cool and fabulous to be used by those annoying bloodsucker vampires. And other secret reason a true vampire never would want to wear a morrion because this is practically a symbol of the Tercios, the military units of the Spanish empire. The vampires hated the Spanish tercios with all their no-soul, because these terminated most of them. If Val Helsin, a simple mature man could kick-ass Dracula some times, then let's imagine one of the best armies of this age, and with the extra help of the "rose of Guadalupe". Maybe I should ask an affirmative action for the carrion-wearers in the groups of cool heroes.
I guess we are not going to see more Magic: the Gathering in D&D but it was in the same year, or a very popular line. Was "Theros" sold really well? In my opinion New-Capena is closer to be adapted to D&D.