Not clear what advantage vi-pipe offers over already available ways to make use of an editor in the middle of a command line pipeline. aka built-in shell functionality, available program(s) and/or OS provided features (aka named pipe and/or redirection to/from editor from a socket).
beginning of pipeline > output.txt; <editor of choice> output.txt; cat output.txt | rest of pipeline commands
sed, stream editor, takes text from standard in and writes changes to standard out in the middle of a pipeline. sed does this without all the extra overhead a standard editor incurs.
More flexibility with awk, but also more overhead than sed, but less than vim.
With a bit of macro magic and/or readning from/writing out to named pipe, can do the same interactively with vim.
