I saw the Di2 idea bout gears, but the most useful feature of Di2 Integration is the ability to program the shifter hood buttons to have the ability to start/stop laps, change pages so you can glance at a larger version of a Map, and change back to workout metrics. Having dedicated pages enables the user to have fewer data fields and larger metrics instead of crowding it on to a single page on such a small screen (M50)...and being able to change pages using Di2 hood buttons allows the user to keep his hands on the bars. Knowing what gear I am in is "nice to have" but not something I need. Hood buttons to start/stop laps, change pages and Di2 battery level are the most useful IMO.
The next most useful feature for me is to be able to monitor Di2 battery level.
Having said all of that, I see Di2 integration has been on the "planned" list of updates for the better part of a year....but can you give us an idea of when we can expect it?