Hmmm, and I don't have MGE either. So unfortunately I can't test any of it. I think it
is actually the version most people have, though. It would be rather nice if you could get ToT. Most new things are being developed for that, and it's the latest Civ2 version.
But let me think. Let me start with some non-gameplay related ones:
How about having Civ2 always start at the default zoom level (= Shift+Z)? On screen resolutions higher than 800x600 it will normally start a game a few levels zoomed in, which looks fairly horrible.
Or what about disabling horizontal movement, for both the human players and the AI? This sounds like a weird suggestion, but with such a change, and a few imaginative changes to the graphics, Civ2 could be changed to a hex-based game (i.e. with hexagonal tiles).
And then, how about the opposite of what you just did? Disallowing city building altogether, while everything else still works for Settlers. That can be helpful for scenarios where city building shouldn't be allowed. We now have to rely on "house rules" to stop the players from building cities.
Oh, do those patches also work for the AI? That is, in your last patch, does the AI also use all units to build cities.
Is there any chance you could change the game to allow for more than 8 civs, 255 cities on a map, or more than 2048 units in a game? That's going to be tricky, because at least with the civs and cities, it would require more bytes for the data in the saved game (and memory), so if this were possible, it would make their savegames incompatible with other Civ2 versions.
And how about increasing the number of units in the rules.txt to 80?
Increasing the number of terrain types? Or, failing that, having multiple "Ocean" terrain types?
Change the map surface value from a signed to an unsigned integer to allow for maps up to 65,535 tiles. Or are they unsigned already and it just needs to be assigned more memory?
Increased memory for events. This is particularly helpful for MGE, since ToT has about 100K for events, while MGE only has about 32K, I believe.
Major objectives don't work in MGE while they did work in FW (cities can be worth 3 points instead of 1, there's a separate "flag" for each). Can you make them work again?
Could you also let Civ2 make use of extra things in the rules.txt? Say, people could make certain units unbribable by adding an extra flag to the unit's rules.txt entry, and the patched Civ2 knows what to do with it? Or how about some custom .ini file or so?
Could you suppress the pop-up you get when city production is automatically upgraded to a different unit? (i.e. the @UPGRADED text message from the game.txt) That would be mighty helpful for
"yo-yo obsolescence".
Allow the building of roads/railroads on water, and more importantly, have land units actually be able to travel along them, while ships can also still cross.
Fix the goto bug.
Fix the AI.
Well, that'll do for now. Some of those will undoubtedly be (next to) impossible. I'm just kinda probing what kind of things you can do. I'm sure there'd be hundreds of other improvements that could be made.