Whether DCC is a must have on the Mk8 will be a matter of personal opinion. Just as it was on the mk7/7.5.
But IMO, if you can afford DCC, don't hesitate. I cannot see a circumstance where you would regret it. DCC gives the car so much more versatility. Whether that's passenger preferences (as in my household) or road conditions.
... it is very much personal choice and circumstances. What cars have you driven before? What are the roads like? Is comfort a high priority? Will you fit 19 inch alloys?
I found the standard Mk7 suspension too firm, but the roads I drive on are terrible. I told my dealer if the car didn't have DCC he could keep it. Many people find the standard suspension GTI/GTD fine.
I suspect they might have improved the suspension from my test drive in the new A3 S line. Despite having sport suspension, I found the new A3 reasonably comfortable.
It is impossible to be sure without a test drive.