The door panel and mirror removal/installation is super easy and straightforward. Other than a few door clips on the interior door panel, nothing should break as long as the mechanic doing the work is competent. I will say that the mirror housing, turn signal LED, glass and bezel all come separate and have to be assembled prior to mounting the mirror, as opposed to the entire assembly coming as one part.
This whole mirror issue has been well documented by Mazda, but they can't seem to resolve it. Here is a brief history that I have come to understand from the service manager as my dealer (he is a great guy and knows his stuff):
1) Original mirror - Mazda issued a TSB which involved installing a steel brace between where the mirror mounts and the side impact beam. The idea was to provide a more rigid mount thus eliminating movement. This steel brace eventually made its way into new production vehicles after a certain VIN (the brace became part of the door structure and was welded to the door, as opposed to the bolt on part provided for the TSB).
2) The fix above did not solve the problem, so Mazda began using the same original styled mirror assembly except this time they put a large gob of epoxy inside the housing. The idea was to increase rigidity by strengthening/supporting the black plastic housing. This also did not solve the problem.
3) Mazda (in the USA) under warranty, began installing the 2016 styled mirrors (introduced to mass production starting in April 2014 for the later 2015 model year) on 2014/2015 models. This also has not solved the problem. However, compared to the original mirror without the brace, epoxy, etc, it is an improvement, but still not considered resolved as the mirror still shakes when driving at highway speeds.
What has stumped me is why the passenger side mirror doesn't seem to exhibit the same problems.