I watch reviews now and then, and the main thing I want to see is what all the cards look like as a whole package. Often you only get to see a handful of cards, and not all of them, and usually you get to see a small picture or a digital representation. Seeing the details of all the cards, showing some closeups, talking about the details are the things that I'd look for.
Handling, IMO, is not all that critical because most cards coming out these days are very similar in stock and finish and there aren't wild variations amongst new releases. I can look at my collection and probably 90% of my decks handle very closely, except for the few oddballs. So unless a deck handles utterly horribly straight out of the box, spending a lot of time talking about that isn't as helpful.
Giving some personal opinion is fine, but a reviewer should always be fair and preface things like that making it clear that it's their opinion alone, and other people might feel completely different. We all have our tastes.
Length wise, I think a good review could be done in 5 min or less.