What you can't spam rmb+space in peace? Poor you!
Why is it empty? Because nobody is interested in pvp? RBF give you exp (a lot of, there are even players who exploited rbf to get lvl 62+ quickly), sp, money and others rewards.
Now you probably understand that pve players are more important, and what they want.
PvPvE players are the most important. That's why you don't get what you want
If you are grinding and somebody comes to your spot and you have better gear then them. You can out grind them and they will eventually leave. If they flag up and you have better gear than them then you keep killing them. There will be a very small chance of where they come to your spot, you cannot out grind or dec them and you ended up losing karma. However it is more likely that they are grinding and you have more gear then them and you get karmabombed. In that case if you have right to flag up they have the right to karmabomb as well. Sorry but pvp is a two way street and should stay that way.
One problem: some classes are very slow, you won't be able to out grind. Also this game never been designed for more than one player in a spot. When two players next to each other start killing mobs, after a while they will have nothing to kill. Problem may not exist in very high zones, but players are forced to play in medium zones, e.g. collect mini parts for treasures.