RvR is fine how it is imo. One side having more players then the other wasn't a game problem. It's mostly the fact that alot of bigger, more organized guilds were on Dione. Eos had a few organized guilds there also but it didn't really seem like people on Eos really tried to rally their side and ask/tell people to get to RvR. That or people just didn't want to show up to help their side get the buff. Honestly I don't think adding a buff/debuff or giving incentive to people to join one side and not the other is gonna work at all.
People like to complain about being zerged and outnumbered and such, but in reality very few people work to address the issue themselves. Example: Messaging other guild leaders and talking to them about RvR or w/e, discuss plans and things with them.
They just want a quick fix from the game makers. And I don't just mean this game. I've seen this happen before.