What you want improved: The /jump command. Reason why: The command gives players with the rank needed for the command an unfair advantage for raiding over other players, it's worse than /fly in my opinion. The command should either be removed or made available to more donation ranks. The command can be used when looking at a base and if there are not any blocks where player is looking at it teleports them in. It in general makes raiding too easy.
Was it recently? I haven't been on much this weekend, have a lot of school work to get in before my senior trip. Anyway, the only way to prevent people from using /jump to get into your base is have the air replaced with lava or water, but even then you can't even set a home to get back.