At least the suggestion is out there. I suspect they are going to make either another full expansion or a sequel and if/when they do, they can use this template to create a very good multiplayer user interface.
I dunno. Right now we have no idea what the devs have in mind for Sins. They might just be permanently done with it.
Considering the fact that what makes or breaks a game in the long run is its multiplayer, I would think putting thought into the multiplayer user interface to make it as good as possible would be something the designers would like to do. I really like this game and I wish more people played it online so if there is a better multiplayer interface, it may result in more people playing online.
If they make a Sins-2, will it even have online multiplayer? They know that only 1 or 2% of all purchasers ever played it online and probably no more than 1 or 0.5% on a consistent basis. The issue becomes, "Do we spend 33% of the development costs on a feature that only 1% of all purchasers will ever use?" Multiplayer is important to me, too, and I won't purchase Sins-2 if it doesn't have an online multiplayer component.
Ironically, IMHO devs and publishers get out of online multiplayer what they put into it. If they release the game in a polished state with good online multiplayer features and build in ways to try to encourage the single player crowd to try it online, then they could get more people playing it online and have more sustained activity. The benefit of online multiplayer is that online players tend to take the game much more seriously and advertise it to their friends more enthusiastically, resulting in additional sales. It also increases general publicity for the game and thus sales.