I just finished a mission on an assembly called "Urban". I realized the supermarket, the disco and the community center, all of which have their individual maps. There were only 5 aliens in total. Aside from that there is not much relation between the map size the engine chooses and the number of aliens, this map is just needlessly large. "Large" meaning ways to go and ways to hide, rather than actual map size. I suppose that such assemblies are created in order to improve map variety, but the cost is IMHO too high. The cost is increase in playing time per mission, annoying search time for aliens and turn waiting time, because the increased size results in sometimes massive computer resource load increase. This is most noticeable on "forest" themed maps, where alien and civilian turns are sometimes *very* slow now, apparently due to a combination of increased map sizes and a new tree model. Forest themed maps used to be pretty small and quick in 2.5 still, but they often have become annoying in 2.6.
