For me, the "perfect panel would have a few improvements made to the door design.
I ought to be able to set the cover in place- so the weight is borne by the panel- and the screw holes would line up.
The mounting screws should be captive, so they don't get lost.
The cover should be lightweight. Plastic and aluminum come to mind.
The cover should have real handles on it, so I don't risk cutting my fingers on sharp edges.

The neutral buss ought not be buried under all the hot wires, and they neutrals ought not be "stacked". Indeed, you ought to be able to tie down the neutrals in a manner that makes clear just which 'hot' wire the neutral is associated with.