I'm very curious about this myself, especially considering they've been developing the game for a few years now.
"It will be extremely rewarding finally to unveil what we have been developing the last several years," said game director and MMO veteran Matt Firor
Although I highly doubt they'll aim for a Morrowind combat-style, not only because it's an MMO but also possibly because it's a different studio developing the game (Yes, I know Bethesda and Zenimax Online Studios are both tied to Zenimax Media, itself).
Saying that, do we even know if it'll be a theme park or sandbox MMORPG?