Regarding AOA and who has what feature. I find the press coverage interesting. Air Canada has a more comprehensive installation, yet the press articles start with 'Air Canada and Westjet' and downplay the role of the AOA indication. I have to wonder, if the situation was reversed, would we see, 'Air Canada lacks important safety component'?
And nothing from Sunwing. Hmm.
IMO the AOA indication's value depends a bit on the aircraft envelope. The Citation I flew a million years ago had it, and it was a straight wing aircraft. Far from being a distraction, I found it provided a great immediate reference in a number of situations.
For the MAX, the AOA location just becomes one more scan item. The pilots I have spoken with about it have no issues and are generally happy it's there. Given what we now know about the link between AOA and unexpected aircraft behaviour, just having an 'AOA disagree' without an immediate visual indication of which AOA is saying what, that creates a period of confusion as to whether the failure is on the low side or the high.
Finally, the AOA indication is not going to be a distraction during an MCAS firing. What it IS going to do is warn the pilots of an impending problem while they are still configured (flaps not yet retracted) so they can decide on a mitigation up front (leave the flaps out for a bit perhaps, so delay acceleration, get some altitude or stay configured and return, etc).
AOA indications are a good thing. The customers who shelled out on their own to install them should get a credit from Boeing when the rest of the world gets them for free.
Finally, as soon as Boeing and the regulators start rolling out the fix, the grounding should shift from total airspace bans to unmodified aircraft and crew. If we don't recognise investment in additional layers of safety, that investment will not continue, human nature being what it is. The reasons for this grounding are ample proof of that sad fact.
All just my opinion.