It seems that the majority of people who see no value in displaying AOA are those who have never used it. It works very well, as I found out when I needed to land at night following a complete loss of IAS, and it works on big aircraft as well as fighters.
An absolute AOA indication (in degrees) is not necessary, far better to have an indexed system, the main point being that it gives you a direct indication of how well your wing is performing - that is extremely useful information when you are near or nearer to the margins, for example on take-off, approach or landing. And if you are on the point of stalling, it is the only thing that will tell you reliably how close to the edge you are. With the right tab data, you can also get a pretty good indication of your AUW by comparing IAS and AOA values, which means you can find out easily if your pax are lardballs who have decided to carry on 15kg apiece - that might mean you being able to add 5kts to Vref in the knowledge that you are maintaining your stall margin on the approach. Would that not be useful information?
I would have AOA displayed any time the gear is down, if the speed is below 200kts (for most large aircraft), or if the stall warner is active. For the latter case, I would bin all other speed cues and display attitude, AOA and altitude until a recovery is obvious. Yes, there will be training required to ensure that IAS-only pilots understand what they are being shown, but once learned, never forgotten.