What should be mandatory in every professional published review-

One major practical issue is that ow the reviewer needs to be familiar with the previous unit.  Or, now his/her work is at least doubled, to in effect, review two products.  In the end, most will not really want that review.  They want to hear about something totally new to them.

And regulating reviews?  Yikes.  what kind of shirt ought i wear if i undertake that task?  Is a tennis shirt ok? Or is a music Hawaiian required?  Hard to say....

here's the issue.  very few of the reviewers you know make their living reviewing.

They are published, yes.  Might even get a few bucks for a piece. but they have real jobs. Its a hobby

@soix 

Just in case it was not clear,  no disrespect at all. No ding on "professionalism". but folks were talking as if they coudl define high end reviewers like plumbers, lawyers or economists.  Heck, mybe behind screen names we know each other, but many of the top reviewers that i happen to know have very different professions. Investment banking, engineering, defense analysts (seriously!).