As it stands it does seem like conquest mechanic is pretty pointless, there is no way that a player can actually affect any sort of change, and i always thought Invasion mechanic had one purpose alone, to get on my nerves, apart from the dubious gain of reputation(which is not that great anyway) it just serves to put a permanent roadblock on your path, unless you face off against all those enemies, but it's not unusual to have 2 or even 3 invasions at the same time in close proximity, which is just too much.
So i would propose to rework the conquest system and make invasions part of it. Conquest would no longer decay on it's own, rather, an invasion could be launched on the contested ground, and if the invasion is sucessful(Player dies or runs away) then the ground is conquered by the invading party, but if it fails then the invading party looses it's influence in that part.
THis is how it would work, for every invasion point in an invasion(1 invasion point = 1 spawned mob) the invading army needs to invest 1 conquest point, at the end of the invasion, all the surviving mobs refund 2 conquest points, so if more then 50% of the invasion dies then the invading faction is at the net loss.
As for fullky conquered areas, they would not be completely safe either, if fully conquered area of one faction borders fully conquered area of the opposing faction then one of the factions can launch an invasion over the border, if the invasion is sucessful then that area becomes a contested ground, but if it fails then the invading faction's area becomes a contested ground.
Reworking the system this way would allow the player to actually have an impact on the world, and even carve out safe zones. Because of the size of the map there should never be a situation where one player was able to just conquer everything(though servers should have an option to make certain areas unconquerable) unlike the current system that is really just a gimmick to make you feel like you are doing something but you are really not.