Let me restate my intended ilvls to refresh: 505 for Disruptron, 525-530 for Lei Shen.Except you're assuming a higher intended gear level to make your argument work.
Exhibit A: 5.1 was released on Nov 29th. Four days later, we killed heroic Sha of Fear. I was ilvl 503 at time of kill, with a normal mode weapon, as listed in the description. Conveniently 140k dps on the kill as well.
Exhibit B: Method kills Lei Shen 25 with ilvl 525. We did it around 529. Paragon did 10m at 523.
Yeah, retry time is quicker on Disruptron which also makes it easier. Dark Animus had higher personal responsibility than Lei Shen, for example, but a weaker dps check and less coordination. Quick attempts were part of the reason why nearly everyone considers DA easier. Regardless, the first kills of Disruptron took fewer than the 200-300 attempts the first heroic Lei Shen kills took.1 is a 2 minute fight 1 is over 10 minutes, 1 has a 10 second run in one has a 1minute run in. I also often find myself waiting around for the slower people in my raid group, have always done for some minutes after I was ready.
Likely a range doing the fight properly, before they figured out the levitate bug? Unless they discovered it on PTR and kept it a secret, dunno.5 hours for a ranged or levitate, or 5 hours for a melee? Other point is Disruptron is significantly easier for some classes than others (I'd imagine Feral has a harder time though).