It's simple to make an unjumpable base. If they took /jump out of the donation perks that would be scamming as some people only bought Elite and up for /jump. I know when someone got me elite I really only wanted it for /jump as Factions is my main game-mode. If you want to know how to make an unjumpable base then PM me.
No Support. /jump is fine. If you think it isn't then why not do what @Daddy said and only disable it in faction claims.
Like what @legends152 said that on opfactions for new players maybe they should add tips to the game like this [console] Tip Elite and above have access to /jump or maybe like this they could have an guide to factions <3 just trying to help