It would be interesting to see a study on the memories/decision making skills under pressure of RTS gamers vs non gamers. As someone who plays a not insignificant amount of SC2 I have to agree with you.
Edit: Addiction habits would also be interesting to study. This may, of course, have been done and I'm just unaware...
I've run across a couple of questions about the value of dual n-back, and this is the best place I know of to find people who've worked with it.
If you've tried it, has it noticeably improved your working memory? Was it enough to be worth the time?