When WAR first launched, we played musical keeps. Now we play musical city sieges. There needs to be a balance between rewarding attack and rewarding defense. I see giant imbalance right now though, and fixing it I believe would correct the issue of not many bothering to defend.
As of right now, defending a keep does not award RvR Insignia, only taking a keep does. Also the Emblems only come from Scenarios. I would suggest treating a keep siege like a scenario. 1 Fused Insignia and 1 Emblem for winning + 1 more Emblem per star of the keep. This should be awarded on the PQ loot roll if you have enough contribution to roll whether you are at the keep at the time or not. I know many will come help attack to get the extra Insignia, but few will defend because it is not awarded on defense. Bug maybe? or intended?
Volkmar is doing another Open RvR night Saturday. I don't not feel we should have to schedule these in order to get some open field action though. People always follow the path of least resistance. People will only defend if they feel it is worth their time.
I have another idea to encourage keep defense that also happens to make MDPS more useful, but I stole it from Aion. Shhh, don't tell the fanboys. More details later.