It's sometimes hard enough to maneuver a single LVT through trees... what would happen if you try dragging along 2 drones when you try to squeeze through tree trunks? Do the drones stop against a trunk, breaking up the formation or do they simply pass right through whatever is in the way? Or, does the drone jam-up stop the LVT that's clear of trees? Driving nightmare no matter what happens.
Consider also that every other vehicle/plane capable of carrying troops gets to bring a max of 10 troops... yet this suggestion would allow 30 troops to be brought to a map room. 30 running troops would present a pretty hard task to mow down 21 of them in a couple of passes to save a base take.
Also, if done to LVT4s (and I know that wasn't the suggestion, just sayin') it would mean 3 boxes of supps, instantly restoring anything with a 30 min downtime. Some don't like the idea of a single M-3 being able to resupp at all; this would surely make their heads explode.