Because Stardock servers will have MOD's Turned off.... To play MP Mod's someone will have to run a non-SD server for that game thus SD is out of the rules loop.
It's the rest of your post that was the problem.
and as such should be considered SP events amongst willing particpants and times for battle lenght are voted on
Assumption #1: Assuming that MP has anything to do with anything. The combat system is going to be the same for both, which mode it's played in is irrelevant.
Assumption #2: That battle length can be "voted on". What if there is no pre-game battle length setting? "Okay guys, we can't fight for longer than 10 minutes, so uh, if 10 minutes are up and one looks like he's losing, just surrender, k"?
It will not be a Stardock concern at that point, nor should they ever concern themselves about it during Development.
Assumption #3: That the developers who advertise their game's moddability as "you'll be able to make new games with it" somehow don't have to concern themselves with making sure their engine (and yes, tactical battle mechanics are part of the engine) works outside of the "sweet-spot-in-our-campaign" spec within reasonable boundaries.
I don't think you actually understood what I was trying to say to the other poster.
He linked the length of combat to the current balance in the beta in terms of the size of armies we can produce. I just pointed out that you can't design a combat system based strictly on the fact that "on a tiny map, it takes over 100 turns to get 10 okay-equipped guys so battles are small". You have to design a combat system that works well for small armies, and scales pretty well for reasonably large armies, especially if you're going to encourage people to create new games with your modding tools.
Multiplayer has absolutely no relevance here.