Mine isn't instantaneous either. And I only have maybe a bit less than a dozen extra maps over the 'vanilla' install. Any time I go to choose a new map, it takes the game a few seconds to open up the map chooser, even if I don't hit the 'refresh' button on the bottom.
Not a big issue, but for those of us that don't own i7's, well I'm sure there are a fair number of us on antiquated systems.
BTW, my A8-6410 Kaveri (4 Cores, 2GHz) also takes some time with some TripleA tasks. Bumping the memory over 1GB actually slowed down the intial load (64 bit, but only 4GB memory installed, btw I have a 500 GB Samsung 850 EVO SSD in said system), so I may drop that back down. And I'm also seeing painfully slow Hard AI turns on my map due to the stacks of doom that have materialized (I'm now playing 3-4 turns of Alien Assault between player turns, AA's CPU requirements aren't that much and this doesn't slow down TripleA all that much suprisingly enough), but that doesn't really relate to this specific issue. I'll post that up in the relevant thread once I wrap this game up (with the save game).
I can live with the initial load times (they aren't that bad for me) but if they can be made more efficient at some point, I'd think that's a good thing. This is an open source project, of course, so I'm just happy to see any progress, and TripleA has been slowly but steadily maturing! Thanks guys! Particularly Redrum, we've needed another talented AI guy that can put the time in for a while now, which is awesome on his part.