I definitely think Honda leaned into the sloped rear hatch design because of nixing the coupe... comparing the 10th gen coupe profile to the hatch you can see that the slope angle of the rear to the tail lights is almost identical (except for a bit of added height on the hatch). I don't mind it, and if you look at something like the Mazda3 hatch, it also is very sloped in the back... this is offset by the available roof spoiler they offer. I think offering an available roof spoiler or wing would be a great option for those of us that feel the rear needs a bit of something to finish it off, but as a current coupe owner, I appreciate the coupe-like profile of the new hatch.
The shape certainly isn't unique to Honda either. The tesla model 3 and Y have similarly sloping rear ends, as well as a handful of other (often luxury makers) coupe-like sedans, crossovers, and hatches.
If it was up to me, I would've leaned into the coupe shape even more by moving the B pillars back slightly, making the rear doors a few inches narrower and front doors a touch longer, and hiding the rear door handles behind the window (like the HR-V) to give it the coupe illusion even more without really sacrificing easy rear seat entry. But a nice window tint will work too.