Similarly to how c.vim shipped with Vim highlights anything between #if 0 and #endif as a comment, it would be nice if VimTeX highlighted anything between \iffalse and \fi as a comment, given that these play a similar role in TeX and are a useful way to comment out large swaths of TeX source.

In a similar vein, it may be useful to highlight the interior of a comment environment (from the comment package) as a comment.