it's a minor point, really, but some players might enjoy a few new achievements themed around the expansion content. examples like:
starbase killer: destroy at least 20 enemy starbases
mining: deploy at least 2000 mines
paranoiac: destroy at least 1000 mines/ build 100 scouts
planet bound: win a game without constructing a single starbase
starbase entrepreneur: earn at least 10.000 credits from starbase income.
maybe there's more, but a handful of new ones wouldn't hurt and would hopefully not be too much trouble.