As oft stated, the slope of the bed's walls makes side-loading difficult. This may not seem too significant day-to-day given the bed's volume, but if you're doing commercial work (construction, professional moving, etc), you'll get a lot of items that don't properly fit in the bed's volume. Even the cladding like on the Chevy Avalanche can be obnoxious, if not impossible to work around with some loads.

The body also doesn't look as ammenable to aftermarket modifications as its competitors. Standard racks and bed rails won't be compatible with it, which are pretty much standard mods for any contractor.

On the more elaborate side, you couldn't replace the back end of the vehicle with a domain-oriented work box.

I think a more utility-oriented cybertruck would have gone cab-over like an Isuzu elf, and used a more raditional, if elongated bed-design.

The tonneau cover and specs are nice, but it needs to function more as a modular platform, and have traditional rear end if it wants to compete broadly in the "practical pickup" space.

Great as a lifestyle vehicle, I expect your average truck owner will get more than enough utility from it, and it'll be a dream off-road. But I don't think most of the critiques leveraged against it are being made from the mindset of a consumer who only occasionally needs the pickup portion of their vehicle.