I'm not suggesting they exist, but is it possible to keep the RvR interesting if one side has continual supremacy?  If a WoW BG is lost, it ends, and you start over.  Does WAR RvR reset?

Are there any mechanics so that if there is a 60/40 inequality, the RvR is still viable for the undermanned side?

there is a video out with that exact info in it, maybe someone can post the link. cant remember witch one it is.

Ok, first off I'll answer your question about reset. Yes, after a capital city has been sacked, which is probably after a week long process, to give everyone ample time to explore the newly aquired dungeons and kill the king.

However, to answer the question in the title of your thread. My personal opinion is no, lopsided servers in beta lead to extremely difficult times for the underdog. However, this was beta mind you and servers didn't really have full populations until preview weekend. During PW, it was pretty much 50/50 which is perfectly fine and with softcaps on server factions, it's just a matter of time before server incentives get the underdog factions more populated, if need be.

there are lots of "BGs" that population imbalance doesn't effect.  But no matter what you do numbers will always be helpful, and a 60/40 split will give destruction (yes, they will have more) an advantage.  however my time on order, heavily outnumbered server-wide, seemed fine.  I simply found a group, and we took all the tier 1 elf objectives and steamrolled any destruction that came near us, we were simply more organized despite being a PuG... we just worked well together.

control points are locked for 15min after you take them, to keep the fights moving from 1 node to another, we were able to take all 4 nodes so that as we were just finishing up the 4th, the 1st one was under attack again.  We could leave nodes behind and keep moving as a small group because of this, no splitting up for us.

talking, staying together... not instantly releasing to auto rez (my archmage can insta-rez with 5x damage high magic... LET ME REZ YOU!) protecting the healers, it all helps and really means more than numbers.  of course when destruction brings 20 to our 6 we don't stand much of a chance besides trying hit-and-run tactics, but I prefer it that way.

RvR is a long battle to a capitol city, and it does sort of reset back to tier 4 where the sides are even, so they can fight their way to the capitol again.

So all in all, numbers matter, but the game will still be viable even with the population imbalance, as long as it doesn't get worse than it was at the end of closed beta (anywhere from 55/45 to 66/33) and a lot of fun... more so for those of us who LIKE being the underdog.

Started typing, then saw Rhoklaw's post and agree with what he said.