have formed the opinion that out of all the systems they have encountered, XP debt was, in their opinion, the worst.
The worst? Worse than actually losing XP and losing levels (skills/spells, ability to wear/use equipment, etc.)?
Look, you can have your opinion, but that doesn't mean that it's sensible. Sorry, but of the multitude of MMO's I've played, CoH's penalty system was by far the least "harmful" -- and I played before they did most of the XP/debt changes (the only one I recall was increased rewards from mission completion). You still gained XP while in debt, it was just that 1/2 your XP went to pay off debt, the other half went to gaining actual XP.
The only other MMO I've played that was relatively "lenient" was WoW. But I feel that it was actually harsher -- it took far longer to get back to your corpse and the repair costs on equipment were relatively steep.
don't make wild, nonsensical statements like the one quoted above
Wild, nonsensical statements? He's not the one making them. You clearly never played EQ, where people would log out and wait for phone calls rather than miss out on an XP rez -- because the death penalty was so severe that it could take a week of XPing to get back what you lost. And that was assuming you didn't lose a level and get kicked back into a hell level.