If they ever fix culling WvW will mostly be a 20 vs 20 across all maps any way - because the rest of the people's rigs probably won't make it through the first week match-ups without spontaneously combusting.
So, it's really a choice between the devil and the deep blue sea.
On the bright side - when those 40 man guild group guilds will shrivel down to 5 mans, it might be the sort of G v G a lot of people keep asking for!