I think WvW could use caverns. 1 per server map. 15 per side, per map (so 15v15v15). or maybe 10v10v10, I wouldn’t go as high as 20v20v20 though. A place for smaller, more group oriented fights. A larger sPvP map with WvW gear, basically.
They start up and you fight until a side wins (caps some objective) and then that provides a bonus to that server for 30 minutes (cavern locks, get bonus, like 3% to power).
You could even weight the fight based on the current WvW scores, 2nd in scoring gets some cavern bonus like 3% to damage while 3rd gets 3% to damage and toughness. Though that is debatable.
Qing for it is something I am not sure about. Should give 5-man grps first entry, then grps, followed by soloers. Only less active servers probably not a big issue but on tier 1/2 fights, could be a real clash for who wants in during prime time. Egos always like to forum rant.