I didn't get the chance to play this mission but from what I gather it seems that having 2 zeus in it might be an efficient counter to the woes of randomization?
Element cohesion
I'd agree that individual elements should drop if not together than at least in a close enough radius. If you want to maintain the whole regrouping element, then you could script a solution which randomizes by squad within the entire AO and then within the squad in a smaller radius (300m or so).
I don't like the idea of everyone being ungrouped as it risk ending up without a clear structure of command (e.g. who's supposed to be on CC?) and we'll end up with a FFA mission where everyone does their thing with their buddies alone.
Vehicles
I'm not a big fan of zipping around in civilian vehicles or commandeered enemy vehicles. An idea would be FIA provided vehicles (primarily trucks), another having helicopters fly in vehicles by sling-shot. ZEUS can also air-drop vehicles easily.
Assuming everyone drops within 5 minutes of a rally point and the points are 5 minutes apart, after 10 minutes the commander will know what elements he has and where, and can make a plan of attack.
You
DID play with us right?
I'd say that's a very optimistic time window given our general competence and even if it would be right, that's at least 15 minutes of the mission where not much is happening.