No! You do not need to be on the same ticket. If you are on the same plane, you can call in and have your wife put into E+ at no cost. You don't need to be on the same ticket. This has not changed.
I wish that along with the inherited status change, United would give us an easier way to accomplish granting E+ to companions on different reservations than calling (and then watching regularly for changes). Setting aside any disappointment about the additional fees stemming from the change, the need for more manual intervention seems bad for both us and United.