Do the sweep jobs where you steal 3 items pay more than a burglary job which is only one item?
I keep getting the same amount from vex for both types of job.

Is this a bug or by design?

Thank you from a curious thief.

Every minor radiant thieves guild job gives the same amount of money. Which is why I only do numbers and burglary jobs. ^^

Thank you. Not the answer I wanted, but at least I know it's not a bug.

no, it's not a bug
and the purpose of these jobs, is to become a full member of the thieves guild.
after that, it's not worth doing anymore of their jobs.
you have to do 5 jobs in every city to become a full member, and collect all the unusual gems.
by the time you are doing this quest, you'll have enough anyway

Collecting all of the gems isn't necessary. I restored the Thieves Guild without doing it.

However one of the gems is not available if you don't do all the quest lines - so I am told - but yeah you don't need the gems.