Well, I guess it would have been weirder had there been Titans but no Dragons. Maybe I'm wrong when I suspect Sylvan and Dungeon are going to be coming back at the same time. Maybe it'll be Dungeon and Academy just because of the classic "Dragons versus Titans" gameplay.
Personally I just want to see Dungeon without the Dark Elves ****. Maybe it would just be a collection of creatures that worship Black Dragons. While the Heroes 5 Dungeon units fit together more, the Heroes 3 units actually complimented each other better tactically. For instance, all three shooters (I'm including harpies here as a shooter) in HoMM3's Dungeon were competent in melee combat. This allowed you to hassle the enemy without really having to protect your shooters, allowing you freedom of playstyle, which was needed to protect your Black Dragons against creatures like Behemoths and Gorgons.
If there's no Dark Elves in Dungeon this time, then Sylvan wouldn't have to come back at the same time. Alternatively, if they do have Dark Elves, then they should make the Sylvan champion unit a Phoenix. Why? Because it makes alot more sense to have Phoenix versus Dragon rather than Dragon versus differently colored Dragon.
I know it would be the first time that more than 1 factions appear in an expansion, but also this is the fewest factions in a HoMM game as of yet. Meh. Maybe they're not even aiming for having all the factions at the end. I really think the series is losing it's roots the more and more games we go away from HoMM 3
You'd think Darkmoor was a ghost town, but instead there's plenty of life among the dead.