It's a couple of things. We've done a couple of 500+ mile trips. At the end of the day, the seats are a bit uncomfortable and I do feel a bit beat at the end of drive.
I came from an '18 GMC Acadia with 18" tires. The Envsion has the 20" tires. That coupled with it's short wheelbase does not make the best ride, even on the smoothest of road conditions. I've done 750 mile trips in the Acadia and felt just fine at the end of the day.
We find that if packing for a week, the Envision starts to feel quite cramped....even just for two.
Lastly is the oddity of MPG. Let me say, I don't really care. I've never bought a vehicle based on it's MPG. I just find it odd that I've taken both vehicles on the exact same road trips. The Acadia with it's V6 engine routinely got better MPG than the smaller Envision with the turbo 4.
As a daily driver, the Envsion is a very nice vehicle. I find on road trips, not so much.
As a point of reference, we are seniors so we may be pickier than when we were in our 30's.