My brother played yesterday during the BWE, and I was there and saw gw.com loading very slowly, same thing as reported with noticeable slowness on e.g. image loading. When I got home same evening, it was as speedy as usual. So I'm not sure if it's YOUR server getting overloaded. And besides, this recent scandinavian BWE is quite small compared to the others, and when I've been to gw.com on the larger BWE's, I haven't noticed anything special then either.
So to me it seems like routers on the path to gw.com occasionally getting crowded or going bad somehow... Maybe that's hitting entire networks "upstream" getting this slowness.
I don't think my brother is a victim of a "strangled" line; we're usually having just fine in-game download speeds from his house. (according to the GW loading screens)
FYI, my brother uses a DSL connection on swedish Telia, and I use a fiber connection on swedish Bredbandsbolaget. But it could be that he currently has no problem anymore...
Something that can help when diagnosing problems like these, is to use the command "tracert www.guildwars.com". It helps to show congested servers along the path to guildwars.com, and sometimes even in which geographic area they're situated. Unfortunately
www.guildwars.com currently doesn't accept PING packets, maybe done by the web admins to minimize the risk of PING floods and such attacks. So this command doesn't work very well.
The site is loading quickly here and now anyway.