The distributors get a bit annoyed when we do official releases too frequently, and it takes about a full day out of my schedule if I do full builds of the game. If we run into anything super serious I'd do a maintenance release without the builds, but we don't plan for those in advance. So far no super serious issues are known.
I for one would be perfectly happy with a one month official patch release cycle just for the performance boosts and general fixes. Especially now that the game has reached a point it can stand on it own for months or even years with the current content if you have all the expansions. Up till 5.0 a combined approach to patching with a mixed bag of fixes and experimental changes made sense but tbh I think the game is at the point it can ride for a while and just concentrate on refining the current mechanics. Been plenty of times when I read the patch notes where I would think that hmmm these fixes would be awesome for the game if only they could be seperated from the reinvention. 
Far be it from me telling you how to do your jobs, but here I go anyways.
How about a 2-3 month reinvention, experimentation, and bug fixing release cycle. Then push that stable version. Then have a 1-1.5 month release cycle for mostly bug fixes and performance boosts (and balance tweaks that don't require reinvention) and release that as a "maintenance" stable release. Repeat.
This way, you sort of get the whole "reinvention betas" and the "polish betas" separation some people have been asking for, but without having two separate code bases. It seems like a workable compromise, without adding that much more in terms of frequency of stable releases.
