Making a release takes time. First you have to have a somewhat stable build. Then you have to compile it on the other platforms. Then you have to perform regression testing and at least some testing of the new stuff. This probably takes 2-3 days purely for the motions that have to be gone through, and the commercial platforms probably add some additional stuff on top of that. An emergency release to fix a single crash bug might get away with cutting down the regression testing to a bare minimum, but it's still a fair number of purely bureaucratic steps to get there.
My suggestion (which has been made earlier) is to aim for a "yes, we're still here and supporting the game" release about once per month during the Big Wait (the start of which currently seems to be 2-4 years away), unless there's a need for an emergency crash bug fix. These releases would include bug fixes of bugs in systems that aren't expected to change in the next arc branch (i.e. the M&M one), and so can be implemented in the current arc (which would then be the Premium + Villains catch up + Army improvements one) and just transferred to the next branch more or less unchanged. Similarly, minor improvements to localized systems that aren't expected to change might fit in here as well (say improvements to hospitals, or introduction of multi hauling for light items [goblin teeth, socks, etc.] beyond plant gathering, to take some possible examples). I'd aim for spending about a week per month on these releases, including the time taken to perform the releases.
I'd like this approach to be taken earlier than the Big Wait, but given that there seems to be a hard time limit for the Premium release with contents candidates that seem to far outmatch the available time, I can see the wisdom in only fixing serious bugs for the "current" branch (Villains) during the Premium arc (and the tail end of that doesn't have any need for extra releases, as bug fixes will have to come frequently anyway). If Villains catch up and/or Army Improvements sections need multiple months of work that won't be fit for release in chunks, I'd make "yes, we're still here and supporting the game" releases during those sections as well, but part of the adaption to the commercial arena will probably be to try to break up things into chunks that can be released: if the "cost" of uninterrupted development is to spend effort on "yes, we're still here and supporting the game" releases, it might be worth the effort to split things up so the chunk releases provide the progress indication (although there's probably no getting around some fixing of non critical bugs to ward off some of the criticism of bugs never getting fixed).
And like Shonai_Dweller, I don't trust darkhog when it comes to the enormous sales that will just roll in. The course is set, though, and we'll see what an entry into the commercial market brings in about a year, hoping (and working) for a good outcome. It's a game by geeks for geeks, and the Premium release won't change that, even though the tile set might lower the geekiness threshold a little. However, it might bring more geeks to find the game, without getting too many casuals/RTS:ers who'll feel cheated when they realize it's a geek game (hopefully with some of them discovering their inner geek and liking it).