I have a good degree in a none technical subject and failed nine ATPL theory exams in total, one subject I failed twice. I was 100% motivated and with what was supposed to be a top ground school. I passed all 14 in the end but I can't see any relationship between having a degree and breezing the ATPL's. Having a technical degree may well provide a good platform to start from. I wouldn't do an aero engineering on the basis of it coming in handy for passing ATPL's though.
The one piece of advice that got me through the dark days of ATPL theory came from these forums. It was to remember that ATPL exams may turn into a battle of attrition between you and the JAA. Hang on in there when things are going badly and if you fail an exam first time, treat it as a live practice and learn from it. Also, if you are struggling with your ground school, be brutal, change to another one. This worked for me.