I think this is more designed for streamed output rather than viewing files. Vim doesn't seem to support that, in fact it just says "Vim: Reading from stdin..." forever.
Hmm.. I guess you could write a little script (2 lines?), let's call it "vimlive" which reads from stdin, streams to a temp file and opens that temp file in vim.
Then with:
command | vimlive
You get vim with the current state of the data and you can update it with :e
Then with:
You get vim with the current state of the data and you can update it with :e