Remember HW2.5 or 3 only affects the FSD portion of your experience. Everything else is handled by the MCU. So things like Netflix, sms, voice recognition, basically every other thing other than FSD would not be affected. I would say (admittedly uninformed and ignorantly) that what we know of today as auto pilot (TACC and lane keep) is pretty much feature complete with only optimizations coming for those with HW2.5
There are some features that those with HW3 but not FSD get, like stop sign, traffic come, and stop light visualizations, but those don’t have a material effect on AP or driving.