All your questions are interesting if you want to play performance games.
WoW is no such game. WoW is made to work on as many systems as possible. True, it does look nicer on higher spec systems, but that is about it.

Only since BC am I encountering issues with an old notebook with a 32MB ATI Radeon mobility 9200, which is a joke as far as graphics go today.

For WoW you want to be sure to have 1GB RAM, a decent CPU, pretty much all you can buy today is ok, a graphics card with a chipset that is less than 2 years old. No special requirements anywhere, unless you count the memory requirement for smooth zoning and smooth playing in crowded areas.