Actually, when beta 3 first game out the overwhelming majority felt the game speed was too slow and games just took too long. You have a good point in why it should be slower, but the example of Multi's Beta 4 video was not an average length game. It was over very quickly; about an hour and 40 minutes, was it?? We played another 7 player game last night, and that lasted a bit over 3 hours.
That said, there are speed toggles built in, and I believe the recorded game we played on Normal (which is actually the old beta 3 Fast). I think if you actually played the game, you would be quite comfortable at the normal setting, it feels just right for us. Since it was put in (old fast/new normal) there hasn't been a single complaint about the pacing, other than the new fast is too fast

A lot of us appreciate that this kind of game isn't meant to be a blitz like some Stracraft or other RTS matches can be, but a lot of us also want to be able to finish games in one sitting in a fairly resonable time - the devs did a poll, and most people voted that a medium game should take about 60-90 minutes, and right now it's a bit over that, but it plays well.
You will find, I think, that on multi-star maps you'll have plenty to do and it will take a while to do it! I've had some games last up to 7-8 hours against AIs (and the AIs right now are pretty poor so they don't put up as big a challenge as they will at release).
The bottom line from me is that I don't think game speed is a particular worry for players on either side, at this stage. People who like very large maps with multiple stars will find they take suitably long, and people who like shorter games will stick to smaller single-star maps. That's one thing games like Starcraft can't do - the maps in them don't scale nearly as well as the maps in Sins!