There were schemes to stagger the exits of the paras from the two para doors of the RAF C130K. The major problem with this I found was the paras desire to get out of the a/c ASAP, to get out of the 'honk box' and get the weight of the kit off their legs. The 'runaway train' that was an operational para drop was always a shock to any observer.
Even if 'staggering' had worked it would have necessitated much longer DZs and if you were dropping wedge and door bundles then the DZ would have needed to have been very long indeed. Couple this with the spread of the paras on the ground and real problems with a swift form up and equipment recovery occur.