I'm fine if you fix this and fine if you leave it. Personally, I've switched to
fido-mode + fido-vertical-mode which doesn't do the [mplete.el] dance.
Personally I'm also fine to remove this complexity altogether, even for
non-vertical Icomplete/Fido, but I think at least Stefan likes it (possibly
others, but no record thereof).
I'm not very much attached to the "[mplete.el] dance", FWIW.
I do think it helps cram a fair bit more candidates in the small amount
of space usually available in horizontal icomplete, so I suspect other
users may care, but I'm not one of them because I don't use icomplete
any more (well, I do enable it occasionally, but it's fairly rare).
Stefan