I like the idea of skirmisher/scouts, and if it's not already in, would love it if alien officers could influence that outcome, and if they were engaged by xenos, or just plain died, then the super aggressiveness could kick in, but not for the entire map, just their sphere of comand.
And I haven't played in a while but it seemed there were too few aliens after Chris's balance patch were it was super dangerous, and has since been scaled back from what I understand, but keeping the same numbers of bad guys.