mixing sci-fi and fantasy,
Personally, I wouldn't call "Steampunk" as "Sci-Fi".
It's an own genre, as far as I know.
I'm hoping Dragon Commander allows us to fight in human form and if not, then it should allow us to land in dragon form and fight with tooth and claw, I can imagine the fun already!
Personally, I do hope that this won't happen - because it simply wouldn't be fun wading through the masses.
A Dragon is big and very powerful - this wouldn't be much fun, at least not in my imagination. There just would be no tactical gameplay in wading through the masses.
Close combat against other Dragons - now that would be something different, imho ...
Like you said. Dragons are big and powerful (especially in the Divinity universe), so if we can't kill a few ground troops, then what's the point of being a dragon? Kingdom Under Fire allowed you to fight fairly decent and some of the heroes were quite powerful (One hero is a demon who can set his sword aflame and send fire across the battlefield, another hero can cast a holy spell which basically makes his troops unkillable for a certain amount of time and makes his strong attacks hit all enemies to the floor) but at the same time, if you didn't use your troops and failed to position them correctly, you wouldn't be able to progress. KUF is renowned for being a game where you had to be good at fighting as your character AND good at controlling an army simultaneously. If you failed at doing one, you'd be killed with ease. Your hero and his/her troops can easily be destroyed if enemies overwhelm them.
Point being, the dragon can be powerful - to some extent - but if the player attempts to just hack and slash or fire breath their way to victory, it wouldn't work. I mean this game is meant to explore the dragon theme a lot further, if we can't even land on the ground as it...that'll be disappointing.
If there were fights with other dragons, I'm hoping some would be where they actually engage in biting each other (like in the dream you have in Divinity 2, where you're close fighting with another dragon), if done well, then I wouldn't mind if ground combat isn't included but it should be...I mean, the game will have to allow us to attack ground troops with the fire breath surely and the hacking with claws and biting (and maybe even EATING!) is just something one player could choose to do instead. Keep in mind, that while the player fights on the ground, the enemies in the sky will still be there, so it's not like the player can completely ignore them and hack and slash through armies.
I mean, archers will surely be ground units right? They'll probably be deadly to a dragon. So it's not like you're invincible if you landed on the ground and started fighting down there...
Do we even know what battles will be like anyway? If we're leading an army, I'm guessing some will be ground troops...maybe all the battles are flying battles, what with it having steam punk elements...I see that this may be the case and this would mean that there are no ground troops but then what units will there be? Different flying Zeppelins with either archers or magic users in them? Perhaps flying machines which fire canons...
I'm still hoping for some ground battles though...I mean we saw them in Divine Divinity...even Divinity 2 had them (Damien sieging Broken Valley, Seekers sieging the Bandit Camp, Black Ring sieging the mines and Undead attacking Aleroth). Such battles can still have flying enemies but you'll also have enemies on the ground.