I had a brilliant idea.
Step 1) Open up a new merit category called, "Experience Points" where you can use merits to add EXP to jobs.
Step 2) Allow people to Merit this and only this at any level.

This will both reduce the amount of "leechers" in Abyssea, and increase the speed at which you level your jobs up since the leechers won't be doing nothing. Everyone is happy!

Just imagine dropping 200k exp on a level 1 job. First time... Ding level 45. Repeat 7 more times, and you have a fully capped 90 job.

Sorry if someone already posted this brilliant idea in the past.