You cannot move safety parameters on the basis of changing a test. That is absurd and you cannot have a more blatant example of positive discrimination than this.
So what is it you want? Everybody to agree with you that colour vision deficiency doesn't present a safety risk? The CAA are taking a viewpoint that by bringing in a more relevant testing regime there would be a greater chance of a candidate with a CVD achieving the new requisite standard for the issuance of a medical certificate. This suggests that elements of the current system could be disregarded in exchange for a more focused and colour perception relevant test. It is their job to discriminate, and anything that does so in a positive manner should surely be applauded rather than derided.
Colour perception is without doubt an important element in flight safety. Difficulties in the distinction between taxiway and runway lighting and the associated nuances at a busy airport, as well as colour gun failures in CRT tubes etc. Is important and relevant whatever you may think, or like to hear. It is also relevant that these standards are not something that is naturally degenerative, but perhaps compensated by correction and experience (such as for example, presbyopia.) This is something that would affect potential candidates at the front end of their would be careers.
If the CAA are moving towards a better or more updated system that will help more candidates achieve the standard, surely you would encourage such a use of "public funds," particularly since this particular "public" is the CAA's customers.