I think his main point was that when a PC falls to negative HPs, nobody, DM included, can predict whether he's just momentarily unconscious or dying. The fact is, in 4E you just become "unable to fight" and fall prone, but the DM cannot describe the effects of the last blow or the PC's condition in any way until those "recovery rolls" are done with. For example, the effect would be laughable if you described how a blow leaves a character with "his guts spilling out", but he rolls a natural 20 on his next round's recovery roll ("Guys, I'm just fine! A bit bloodied, but no lasting wounds!"). Especially as he only needs to rest for 6 hours to get to "full health" -- quite a feat if he's innards were hanging out.