I have run FW and marine tanks before with UGFs and found them excellent. I ran mine with airstones. Never had an issue with filtration in those tanks. I did have one once where the plate was smaller than the tank. The gravel in the couple of inches where the plate was not got MUCH dirtier than where the plate was.
If you want to improve filtration, add a filter, but I see no reason to remove a very efficient filter.
If you want to improve filtration, add a filter, but I see no reason to remove a very efficient filter.