Pain killer was/is extremely good at what it does, and great for doing it well on a limited system too. I found it very one dimensional.
As for retrospective reviews lets hear it for my personal favorites Stalker and World in conflict.
Point to note, lets hear it for just one single RTS!?!?! So long as it's not Generals or anything C+C related for that matter. Like EA, it's just how many times can they re-release the exact same game with minimal changes in the graphics? Like Warhammer 40k (and I loved that) but that's just the same concept as Starcraft1 ,2, and Warcraft 1,2,and 3 in a different dress.
Other than Shatter Galaxy it's been a long time since I've seen something new on the RTS front to be fair...