welcome to the inner circle
Noooo! Don't release information about the Secret Squirrel Society!

As far as system requirements, my thinking is you can compare it to Dalaran.
If you can run 5 box through dalaran without studder or skipping, then you're likely golden for the expansion.
If you can run 5 box through dalaran with a few hiccups, but can single-box through dalaran without studder or skipping, then you're ok - you may experience some graphic lag in major cities or scripted events but otherwise play should be smooth.
If you studder or skip in dalaran single-box, you're likely in trouble for multiboxing the expansion.

I know Dalaran is unique for the amount of people crammed in one area, plus the fact its almost a whole zone floating above another zone with causes the server twice as much resources compared to less active zones. And dalaran has a lot of details graphics, or small objects (cups on tables & players' armor for example). A lot of stuff in one place. I figure the expansion won't have so much crammed into one space but updated graphics will still take more PC resources then anything else in WotLK. I don't PvP, but maybe Wintergrasp is a better example - idk.