For instance, I felt it was more useful to spec ACC than a sunroof and these do very different things. 
More usefull for what?
A bloody sunroof doesn't affect the performance of the suspension or the steering!
Neither does DSG.
They are entirely different.
If it's a toss-up over certain options for a fixed sum of money...then I suppose you weight them all up.
But I can't believe many people walk into a dealer and say "I don't want to use either my left leg or left arm whilst driving my Golf...so I'll buy ACC/Sunroof"
They all do COMPLETELY different things!
If you want to tweak the chassis set-up, you buy ACC.
If you want the option of driving an Auto, you buy DSG.
If you like the extra light/fresh air, you buy a sunroof.
But none have ANY impact on the other...so are therefore the only reason you'd spec any of them is if you wanted that specific functionality.
For anyone to say DSG is 'more important' than ACC, is plain stupid.
It's obviously not 'more important' if you want a manual gearbox and the ability to change the chassis behaviour, is it?