Put a button on the paperwork drawer like the Volvo has because every time I go over a bump it slides open and it just gets worse the older the lorry gets until you end up having to wedge it with cardboard to keep it closed
And also redesign the door locks because they are far to easy to break into
The ability to lock the steering wheel in a more upright position.
More height to the windscreen - tall people with long legs sit higher with a taller torso means the top of the windscreen is too low.
Change the location of the fog/work light buttons from the side of the steering column so you don’t have to take your eyes off the road to see where they are.
Proper suzie holders on the rear of the cab.
Get rid of the stupid 2 tank fuelling system or make it possible to fill both tanks using just one filling point.
Flat floor
Redesign the drawer at the front
Sunroof (Glass) as standard
Arm rest
LED lighting all round
Factory fit style radio that doesn’t blind you at night
Removal of top bunk unless specified
Redesign pull out fridge
Rotating driver seat
Better exhaust brake (Rather than the retarder)
seth 70:
Get a volvo
b*llocks 
burnley-si:
seth 70:
Get a volvob*llocks
Ok i will compramise ,get a volvo [put a v8 in it and use the interior switches for the door etc off the scania because the new volvo has some well iffy new bits of trim]hows that sound si 
a speed limiter
as well as cruise
Flat floor
Brighter cab, ie a glass sunroof, better coloured dash, I’m in a 64 plate scania and the dark dash m cupboards are depressing when your living in it 5 days a week.
Cupboards rather than bunk bed if bunk is not required
Simple things like bluetooth and USB ports, come as standard on £40 cheap and nasty stereos out of halfords but are still optional extras in scanias,
12volt socket in bunk rather that 24volt would be more practical I reckon…