Not sure if it's relevant but it seems that the particular A320 in question was nearing the end of its natural lifespan which does raise the possibility that the crash was caused by some sort of mechanical malfunction:
The aircraft involved was an Airbus A320-211, serial number 147, registered as D-AIPX. Its first flight was on 29 November 1990, and it was delivered to Lufthansa on 5 February 1991. It served with Germanwings for the first time in 2003. It was returned to Lufthansa in 2004 and was re-transferred to the relaunched Germanwings on 31 January 2014. The aircraft had accumulated about 58,300 flight hours on 46,700 flights. The original Design Service Goal (DSG) of the aircraft was 60,000 hours or 48,000 flights.
Source:
http://en.wikipedia.org/wiki/Germanwings_Flight_9525