Coward has justifiable grievances with the UCB mathematics department. It must be extraordinarily depressing to work hard at exposition of lower division mathematics to a class of otherwise largely unmotivated students, only to be fired for doing so.
Having said that, I am going to adopt a somewhat contrarian viewpoint. The math department fired Coward for deliberately and repeatedly subverting their requests to conform to departmental standards [1]. It is not surprising that behaving in a fashion that continuously pissed off senior faculty (with the power to fire or initiate the process of firing) got Coward fired.
Coward's student ratings were consistently high. Based on anecdotes, he sounds like an instructor I would love to have (he spontaneously derived a formula!).
However, this does not matter because Coward refused to participate in the system. What I term 'the system' is the set of departmental norms and standards that exist as they do for very good reasons. These reasons might not be understood by all actors.
My understanding of the state of the system is informed by the following:
UCB is an institution that trains thousands of students in mathematics annually. They have a large faculty [2]. The numbers of people involved imply that there is tremendous variation amongst students and instructors - in areas such as raw aptitude, experience, language proficiency and motivation. The benefits of systematizing the process of training in a university of Berkeley's size are manifold. The system has to exist the way it does in order to produce large numbers of adequately (and usually only adequately) educated people. The purpose of disallowing faculty from deviating from such standards is to allow the system to function independently of the people involved in it. There are many disadvantages to this approach, such as stifling lecturer creativity and disabling course-level optimisations (like a particular professor's vivid geometric intuition for something abstract).
I could enumerate the reasons the system exists as it does (at length) but do not have space here, so here is one example:
Using a standard textbook means that course content is instructor invariant. This makes the level of training robust to shitty lecturers, who necessarily exist in any sufficiently large system. It gives students recourse to a standard reference they know is correct. It decreases the variation in quality of students. This is particularly important for co-requirements. It is a huge problem when course B depends on course A and students do not have a firm grip on course A. This happened to my class: we arrived in applied mathematics 3 with a totally broken knowledge of multivariable calculus.
Essentially, the system exists as it does to provide a lower bound for the quality of training. Some people will be incompatible with it. UCB should probably have been more gentle in their handling of Coward - he was 'suicidally depressed' - but I say this with the benefit of hindsight.
[1] >> On September 22nd, 2013 he wrote in an email "But I do think it that it [sic] is very important that you not deviate too far from the department norms." On November 12th, 2014 he wrote "I hope that, on the basis of our conversation, you can further adjust to the norms of our department."
[2] https://math.berkeley.edu/people/faculty
[3] One might think that mathematics is mathematics, and any reference material on a topic will do. I can tell you from experience that this is false. A complex analysis novitiate trying to sort out what 'holomorphic', 'analytic' and 'complex differentiable' all mean will inevitably run into equivalent but different definitions.