Perhaps Siemens should have spent less time putting the units in a massive freezer and more time checking that they could operate as designed on the infrastructure available. There will definitely be a fecal matter/air conditioning interface when one of these bad boys sits down at East Croydon or Herne Hill because of juice problems.
Crash testing issues aren't an unusual experience for manufacturers - Volvo, Jaguar and Lexus amongst others have been given four star Euro NCAP ratings instead of the expected (and needed) five star ratings, because of very minor issues. The manufacturers go away, look at the crash test data and revise what it is they need to revise, and re-submit their product.
Volvo revised the detonation sequence for their multi stage airbag, so it remained more fully inflated for a little longer in the crash, Jaguar did likewise, and Lexus made changes to the lower trim on one of their models, so it deformed in a slightly different shape, keeping it away from the ankles of the driver and passenger.
Siemens has almost 20 years of experience operating their products on the UK network on both AC and DC routes. They have generated significant amounts of data from their own on-board monitoring and have access to Network Rail's infrastructure monitoring data.
The Class 700 units are a result of all of Siemens experience, which has resulted in the winning Golden Spanners for reliability and has seen them continually pushing the envelope when it comes to Miles per Casualty (MPC) and Miles per 5 Minutes Delay (MP5MD).
They put the Class 700 unit into the freezer at Vienna Arsenal precisely because they have data from their current units which show the temperatures they've experienced in squadron service, and need to expose their new design to the same conditions, they've identified reliability modifications and little changes that will help fitters and drivers, but need to confirm they work as expected, with no unexpected side effects - like improved drainage holes which promote icicle formation in the right conditions.
The formation of ice is just one of the many enormous issues that need proper testing - wind chill and the way water is moved around at low temperatures can result in some very unexpected ice formation, we wouldn't want the Class 700 unit forming long/heavy icicles on the roof, as they could be dislodged and thrown up in the air, ending up damaging the pantograph or OLE, hitting windows or damaging signal heads.
Shoe gear is equally important - you do not want ice forming and causing conductance issues with the shoe gear, nor do you want ice forming on top of the shoe and causing it to drop/fail, leaving you with a damaged unit or broken third rail. You don't want ice forming in door pockets and preventing doors from opening, but you do want rain water to escape and for debris to be prevented from entering the door pocket.
That's just some of the issues Siemens have to deal with and why the climatic testing at Vienna is vitally important. It's precisely to reduce the risk of the unit sitting down at East Croydon or Herne Hill.
I don't expect any major issues on the stock entering service - once it's allowed to enter service, but I do expect lengthy and on-going issues fine tuning the computer systems to cope with interference and harmonics issues on both AC and DC systems.