I agree with both sides in a way, but not entirely. Some maps should be larger, but not all, in my opinion, both the campaign maps, and skirmish maps.
Similar to starcraft you'll have the small maps which are based more into rushing, or faster games, lower in resources, or the larger maps for your bigger macro games, although dragon commander doesn't offer that much for macro other than selective factorys and unit choices... :P

I've found in some cases, doing the skirmish maps from campaign, I won't need to even bother with getting the dragon out every turn, as it's over and done in less than 3 minutes. However that isn't always fun of course, I enjoy playing the dragon, but I also like the short games too. A mix of both in my opinion would be great, and with the limited map pool, or stance on campaign maps atm, the shorter games tend to be at the end when there's no units for my enemy left. lol

I'm no balance master so I'll leave most balance up to the pro's and Larian, however the game time generally could be shorter in some way, but I don't mean to add more to Larians plate with the impending launch time, as this is perhaps one of the more trivial of issues, at the moment...