The problem persists. Most flights are delayed (regarding the simbrief EOBT) and we have to wait,wait, wait - only because empty baggage tugs has to leave first, before loaded ones come back.
But that's not what's happening.
As explained in other posts too, the full baggage tugs that are coming are NOT the same that that went away empty: there are TWO set of tugs when calling Boarding: the empty ones that goes away and the full ones that are coming from another parking, and they both start at the SAME TIME so no, it's not as GSX is wasting time because it's making the same tugs going back and forth, they are not the same tugs, which is what you seem to have assumed here.
This means, the time it takes for the full ones to arrive it's exactly the time it would have taken even if there weren't any empty tugs to begin with: it simply the time it takes due to the location of the starting parking spot, which depends where the scenery developer has placed the parking of the "Vehicle" kind.
About the supposed too long waiting time, this should have been fixed in version 2.4.5, released April 4th:
GSX (all versions) NEW: Vehicles coming from afar will come faster, by accelerating depending on their distance from the user airplane, which will help reducing arrival times at large airports with vehicle parking spots not well spread.
This has nothing to do with the reality.
I agree, in reality the Vehicle parking spots are placed fairly close to the terminal they are supposed to serve, and if the airport has multiple terminals, there are also multiple staging areas for ground vehicles. That's how reality is, and that's how airport designers are supposed to design airports. If they don't care about ground services, it's an obvious flaw of the scenery, just as if it contained wrong parking types and sizes, which would mess with AI.
But again, the current GSX version, with the automatic acceleration feature, should have reduced waiting times quite a bit, on such badly designed airports.