Actually, the number of ATR F/O's required in SJU is fairly small. A lot of locals like that. Some drunken yahoos who are single and want to fly around the Caribbean with access to $2 bottles of Rum also like it. MIA is a fairly small ATR operation as well.
Eagle's biggest shortage is (and will be) in Jet F/O's in U.S. bases, like ORD and soon DFW.
But don't think you'll upgrade fast. Once the flowbacks are gone in 1-1.5 years, movement will likely slow again. If you want a fast upgrade, cut up a peice of wood and go talk to Johnny O.
He's always on the lookout for more whores to maintain his wealth.