Could you link to one of his negative reviews?
3 seconds in Google
http://www.ocregister.com/ocr/2005/08/15/sections/business/article_634323.php
Microsoft's mouse is better than Apple's
Clashing design goals make the Mighty Mouse harder to use than competing mice.
By WALTER S. MOSSBERG
Wall Street Journal
A trickier challenge: find a Mossberg Apple review (a full review, not an excerpt) that fails to mention any negatives! He disses Apple on particulars all the time. Or for that matter, find a reviewer you prefer: one who is more likely NOT to say nice things about Apple products. The fact is, irritiating as it may be, Apple stuff tends to please reviewers in general, not just Mossberg. And like Mossberg, most will also point out negatives along the way.
"Mossberg usually likes Apple products, therefore when he likes Apple products his opinion is paid for by Apple under the table" is always a good stance to parrot, though

People should keep that one in the arsenal for sure

Reviewers who sometimes appreciate ease and simplicity and great industrial design, and sometimes don't appreciate it, are MUCH more to be trusted than ones who are consistent
A lot of you seem to be quite confused as to the point of the Apple TV. It is NOT a niche product. Quite the opposite, in fact.
Let's come at it from the other end: Apple wants to be your content provider for ALL media. Music, TV shows, Movies. Not a bad goal, and Apple seems poised to be able to do it.
Apple WANTS it, yes

And it could even be a good enough system to appeal to a lot of people. Someday!
For now, it IS a niche product, beacuse Apple canNOT be provider of all (or even most) video content. They simply don't have the content.
It's a step towards something more in future, but what they can offer AppleTV users right NOW will meet the needs of only a small niche.
So "it's a niche product" is true. And "it's much more than that" may also be true--eventually.
EDIT: And no, there's no technical reason the device could not cheaply support older TVs. Apple's simply not interested in that (not-so-tiny) market it would seem. Maybe so the menu text can be smaller and still readable?

I know Apple probably wants to push HD at some point (maybe even soon) but they could still sell units to people without HD sets.