How about a system where it costs the aggressor as much to knock something down as it takes the defender to build it in the first place? Again, I point to the successful EVE Online model. You don't just waltz into a hostile system on the spur of the moment because you have a sudden itch to 'knock shit down.' If you try that in an even marginally organized hostile system, you get your head handed to you on a stick. (And if the hostile system isn't even marginally organized... well, maybe there's a lesson to be learned from that too.)

I'll say again what's been said several times already: IF the PvP is for a purpose, IF it's true competition with victory going to the better prepared, better organized contender - aggressor or defender - IF the system takes into account the fact that to have carebears supporting your war economy, you have to make some allowances for their orientation toward something other than 'all war, all the time', then I'll be here for a while. But if Xsyon becomes just another gratification fix for people who only want to 'knock shit down' because it makes them feel like they've accomplished something, do it without me.