What should be mandatory in every professional published review-

Amen to that. Fastest way to ruin reviews, demand what they must and must not be. This is probably a tough one to explain, but people's opinions are really only valid to the extent they are the sincere opinion of the listener/writer. The more you let anything intrude on that, the more you are reading about the influence and not the genuine impression. In other words, if you are gonna dictate what must be in a review, go get the gear, listen, and write your own review. Probably be just as good if not better. And then you are in the game, not Monday morning quarterbacking.

Honest comparisons against speakers, amps, preamps, of similar caliber is my answer. Previous version of the same brand previous model or other brands of similar perceived quality. 

This would be almost impossible to implement. Most equipment is loaned by the manufacturer. The reviewer won't have a component from two years ago, sitting around. The manufacturer won't be interested in shipping old product out for review. Nice idea, but unlikely.

Thanks,

aldnorab

Telling people what they have to write doen't ring true with me.

An unintended consequence of the internet is that people have figured out how to use it to poison competitors and pump up their own equipment, often in the form of "reviews".  

Unfortuntely readers are often not smart enough to figure this out.

Jerry

Not Mandatory....but....some things I would like to see because they would be helpful to potential buyers:

1.  Take your own photos...top, bottom and back...and obviously the front and if it is speakers, grill on and grill off...why the bottom...I might care about the feet or the holes, or anything else that can be seen.

2.  If its an amp, then use you IR gun and shoot the amp in a bunch of locations...how hot does it get near the bottom, side, back...maybe I'm using a somewhat closed in cabinet and I care if it reads 95 degrees on the top but 120 on the bottom left.

3.  Show me another photo or two of the packaging.

4.  And if the article/review doesn't have room for the photos, no problem, post them elsewhere and give me a linkl

5. What are the problems that might bug someone...does it click, or pop, or hum or anything on start up or shut down?

6.  The sound...the more comparisons the better....and don't just use "audiophile" music....use some stuff that people actually listen to beside audiophile music.

7.  Say a few words about your own bias...what do you like, what do you not like.