I generally concur with that opinion, although I would have stated it in far fewer parargraphs and bullet-points and I would counsel you to do the same. (“Preachers” tend to get crucified, even if their message is immortal.)

Simply stated, I think that “shell scripts” are intended to be just that:   a moderately sophisticated way to tie shell-commands together. Nothing less, and nothing more. Shell-designers weren't trying to invent a general-purpose programming language (like Perl) since such languages already existed. Instead, they gave you the ability to use any command-processor you like, through the simple mechanism of (#!commandname) “shebang.”

A shop should agree upon a working-standard and then stick with it. But they should make sure that they're using the right tool for a particular job. All you'll get for the wasted-time that you just spent proving that a wrench can be used as a jackhammer is maybe “w00t! w00t!” (While you're perfecting your curious monstrosity, your colleagues are munching fish-n-chips down at the pub.)