Have to disagree with less micro-management, Frogboy, especially early in the game. In GC1, my first act was to create two governors (one is for normal colonies, one was for larger colonies that would produce the bulk of my military ships), and as I colonized a planet, assign it to one of the two govenors. As I got new improvements, I'd assign them to one or both govenors, and the only time I intervened with a planet controlled by a govenor was for morale issues. On the other hand, every time I took an alien colony intact, I'd spend a minute or two stripping out all the stuff I didn't need/want, usually saving 20-30cr or more per turn in maintenance fees.
In GC2, when I get banks, I have to go to every world that I want a bank on and add one (or more), same with mines and all the other improvements that you don't start with. Your "at most" clause is my "at least" as it would at least eliminate going back through all my worlds to place improvements that are upgrades to existing improvements. Hmmm... There may be other ways to do it, without individual govenors, something similar to the military govenor of CG1, that would let me say "queue an upgrade for basic starport to improved starport" but there's still many times I wouldn't want to do that, and would wind up having to go through by hand and deciding where I want to do certain upgrades. Think players that use farms to control population, hence morale.
On the other hand, I can see where govenors are going to be a pain in GC2. Tell me the number of tiles I've got, and I'll tell you what I'll put there. Tell me how many of each bonus resource is there, and what goes on the planet can radically change. I don't see a way for GC1-style govenors to handle that kind of complexity, unless we get more govenors.
On the other hand, I just thought of an alternative that might just work, though I'm not sure if the general public is ready for it. How feasible is this, Frogboy? (I don't see any programming issues, but since I don't know your code, that's a hunch at best.)
First, we need a way to designate tiles for improvements that we don't have yet (O.K., need is a little strong, since I offer an alternative two paragraphs down).
Second, we need a way to group colonies. Call it a govenor, call it a category, call it George for all I care. District? Nah, districts are usually laid out geographically, not by category/type. Attach them to bureaucrats?

Or maybe attach them to commities? Assistants? Paper pushers? Being able to have a colony as part of multiple groups would be very nice, but not necessary. Being able to name the groups would also be very nice, rather than numbered or fixed name (now where did I put my list of planets that were my primary ship producers?).
Third, we need some commands to issue to groups, like "upgrade all improvement Xs on these colonies to improvement Ys", "switch military production to ship Z", or "build one improvement W in any unreserved tile, preferably a tile with a matching bonus, failing that, preferably a tile with no bonus." Oh, and maybe a "build one improvement V in any unreserved title that does not have a mismatched bonus, prefereably one with a matching bonus." Ultimately, even go so far as "build one (or more) type U improvement on each colony in any available tiles that have matching bonuses."
Finally, we need a way to do next-colony/prev-colony within a group, for those times that we need to analyze what we're adding, but don't want to go through the entire list of colonies looking for the ones that need the work.
In retrospect, items 2 and 3 are the critical ones, item 1 (probably one of the harder items) only needed if we don't get the W and V options of item 3 (even just the W option reduces the need), and item 4 would just be really nice to have. It still feels a little like micromanagement, but much better than what we have now, and probably suits the game much better than GC1 style govenors.
Then again, I'm the kind of programmer who thinks in terms of sets, so this kind of organization makes sense to me. I can't imagine having only item three and going through a list of all my colonies and ctrl-clicking on the ones I want to modify, though that would be easier for normal people to get.
With the direction GC2 colony management is going at this time, with "At most, we might have govenrors who set certain buildings to upgrade to other buildings as they become available" type govenors and no other way to reduce the micromanagement, I'm going to spend a lot less time playing huge/gigantic maps, my favorite pasttime of GC1 (well, of any game really, I like room to expand my empire without having to take someone elses territory right off the bat).