You raised a fabulous question I've been chewing on: "dumbing down arrangements", especially on "Almost". Since I write in a lot of styles, it's a conscious choice for me, and I'll explain why:
it's a matter of using a vocabulary your audience understands.
If the audience was just you and me, for example, we could sing 12-tone rows and poly-chordal arrangements, and groove on those. I've written some of those. Contemporary acapella lovers can go pretty far afield with nameless chords, poly-rhythms and hair-pin changes of style - if that's your audience, you write for them. I suppose the far extreme might be cartoon character Hank (King of the) Hill saying "I like both kinds of music, country AND western." - for Hank's ilk, you don't even sing a 6th chord because they'd hear those chords as "errors"
Kinda like singing in Latin or French - right for the right crowd & wrong for the wrong crowd - depends on how well your audience knows the vocabulary by the time you are done.
Now consider what little we know of the judges of the Forest Grove Barbershop Ballad competition and the opinions of the coach we had who has judged that event. Recall in "Nose to Nose" that his ear objected to the no-fifth chord at the end and wanted a full chord. In "Wink", one sixteenth note of an open fifth chord ("old jalopy") needed a third to be fixed, and we did it and will do it. But this gives us a strong clues on what vocabulary his barbershop audience will understand - and it doesn't include 2 note chords. By extrapolation, most of the audiences we will have will understand BBS style, since our agent Tom's contacts are in that world.
"Almost" uses vocabulary the barbershop crowd will ALMOST but not quite understand: open fifth beginning, (to that ear, making our first sound to sound "wrong") major 7 9 6 chords in tag ("al-most like"), and the swipe ending the intro.
Generally, the mutually exclusive alternatives are:
- present and teach a new language entertainingly.
- let the audience dislike what you are doing.
- cater to the audience's familiarities
- re-arrange the tune to the style (I don't like the idea - the arrangement we have has it's own quirky charm, and I personally LIKE those quirks, so we use it in less judgmental moments in performance)
- accept the distrust the audience will give us by doing it the way we like, but hopefully redeeming ourselves by educating those ears to a new vocabulary (Don't like this risky plan, either) or
- choose a different tune for that audience.
Simplest and most respectful answer: choose a different tune.