I think similarly to Sprint mode, there should be a warning of limitations, and as for everything, practice makes perfect and so being aware you're in hypermile mode, you'd take necessary precautions, be it hazards on a 8 grade uphill slope, or whatever
But just a way to really maximize efficiency that won't have so many variables as it does person to person, to make it easier to ger consistent 4+ mi/kw
That's all I'm asking for. And if this means limiting top speed to 70 mph, so be it, being in that mode, I'd be aware of its limitation and won't try to pass someone in that mode, I'd switch to smooth to pass then get back into hypermile mode.
But when camping in the crazy rural areas of Utah where there's not even a gas station in sight for more than 50-70 miles, extreme planning and hyper mile modes may be needed to ensure consistent behavior to get in and out from the destination.
That's my wish list item lol