> Common Lisp in particular is extremely unfriendly to threading macros. Arrows imply a consistent thread-first or thread-last functions. But CL's standard lib is too inconsistent for that to work. So we're left with picking an indentation style we don't necessarily like.

Diamond arrows exist, you know.

    (-<> foo
      bar
      (baz)
      (quux 1 2 3)
      (fred 4 5 6 <>)
      (frob 7 <> 8 <> 9))

All in all, this post reads like a rant, and I realized that upon reading "now what I'm about to suggest is likely not to your taste". That style of indentation is something I use often when writing calls to long-named functions like COMPUTE-APPLICABLE-METHODS and I haven't ever thought of it being not to my taste, or even of it being ugly as the author suggests.