I appreciate the efforts toward bringing technology advancements into scuba. The biggest problems I've seen with the HUD integrated masks is weight, which then impacts fit and comfort. The other issue is the risk of losing your computer if your mask falls off (Sounds crazy but I know a guy who had the Oceanic Datamask and it sank into the depths Day 1 of a liveaboard trip). I'm going to keep the scope to rec diving as I think tec divers would be very slow to adopt this and would have a different set of requirements.
I feel like finding a way to keep the weight down is essential.
Some ability to adjust the location of the display (In the shop the Oceanic Datamask could be hard to read if it wasn't positioned perfectly, I never dove it so can't speak to if this was the same underwater). Adjusting brightness would be nice to have. Other customization options are luxury.
As another mentioned, modularity could be good so mask fit isn't as limiting and you don't need a ton of models.
Need to haves (imo) - Air pressure, NDL, Time, Depth, ascent rate monitor.
Nice to haves - Compass/heading.
Dream/Shoot for the moon ideas - Check air pressure on other divers if they have a transmitter (Divemaster able to do a quick survey of group), fish id, brighten/dim what you're looking at, ability to set a route and have an indicator and where to go, something to show direction/speed of current.
That's all off the top of my head before I'm done with coffee so ymmv, but hopefully some ideas to consider. Good luck!