I think a part of the problem with other people filling the "vacuum" left by Eliezer is that when he was writing the sequences it was a large amount of informal material. Since then we've established a lot of very formal norms for main-level posts; the "blog" is now about discussions with a lot of shared background rather than about trying to use a bunch of words to get some ideas out.

That is, most of the point of the sequences is laying out ground rules. There's no vacuum left over for anyone to fill, and LW isn't really a "blog" any more, so much as a community or discussion board.

And for me, personally, at least, a lot of the attraction of LW and the sequences is not that Eliezer did a bunch of original creative work, but that he verbalized and worked out a bit more detail on a variety of ideas that were already familiar, and then created a community where people have to accept that and are therefore trustworthy. What this "feels like on the inside" is that the community is here because they share MY ideas about epistemology or whatever, rather than because they share HIS ideas, even if he was the one to write them down.

Of course YMMV and none of this is a controlled experiment; I could be making up bad post hoc explanations.