Hm-m, yes, "worth of mortals at the expense of their spirits"... That's close. Still it is not seems to be univocal proof of that concept, as case of Nerevarine may be (and must be, IMHO) rather unique.
Well, I was sorta referring more to the bit about the "receptacle." And in the context of the dreamsleeve process the Nerevarine is a unique case, as his soul would have had to have been kept clear of the recycling process in order to enter back with the full essence of Nerevar.
What about Sharmat, who "sleeps at the center"? Did he communicate with dreamers through Dreemsleeve as well?
http://www.gamesas.com/bgsforums/index.php?showtopic=855475&hl=
Does mortal, who visit Vaernima's realm in nightmares, also goes there through Dreemsleeve?
I'll admit that I haven't thought about this in quite some time, which means I'm just making a guess. It can probably argued both ways. On the one hand, I can't think of anything offhand that specifically says its not the dreamsleeve, however I'd be more inclined to say that Vaermina's connection is more of a direct metaphysical to Nirn in the form of dreams. When there's lots of destruction, Dagon can present himself, that's his connection to Nirn and its also a natural part of Nirn. Dreams are Vaermina's connection - I'd like to know whether the line about slipping into Vaernima's realm could be interpreted as Vaermina's realm slipping into Nirn/your mind, does it really make a difference?
Probably not especially helpful, I'm not in a good speculating mindset at the moment.