back in ffxi you had 24 / 48 hr respawns with 6+hr spawning windows... Don't complain about 2hr ones :P
Lottery spawns ; ;
I am appreciative of the fact it's only a 2 hour timed spawn. Heck, even though Shikigami weapon was a 21 hour timed spawn, he was a bit of a PITA, because he's invisible. Less of a pain if you had widescan and easy when you've got his time of death too (how I managed to catch him), but still, I think we're lucky on SW:TOR in this respect. Heck, at least we don't have to do weapon trials either.
Saying that, there's no real reason to do it for Nightmare Pilgrim. The point of it in FFXI was to make certain items a lot rarer, though it was one of the frustrations with the game, but still, getting that Yinyang Robe was something to boast about afterwards and there's many other items out there like that, some a lot more ridiculous.
As far as I understood it, the timed spawns here were to stop groups of people spamming the world bosses and having the lockout stops that, so no need for the 2 hour gap, at least IMO, it just means another group could potentially just be sitting around doing bugger all until they can spawn.