I think a 2mm fillet around the main display and some filleted chamfers around the LCD switches looks nicer than squared corners. The LCD filleted chamfers were done to make the centre button look better with the cutout for finger 2.

The main thickness has been increased to 22mm and the radius of the inside curve is down from 23mm to 21mm. 

The design of the finger keys stems from the thumb key, which needs the top and bottom material of the enclosure cut away so that the thumb can press it without obstructions. Also, the depth distance between the top of the key and the screen is 0.8mm, but it looks larger than expected. 

The distance between keys is 20mm, which doesn't leave much space around the 17.6mm LCD screen after the minimum wall thickness and clearances.