I can't say I agree with the general diagnosis on this one. He certainly has more than enough valid criticisms, such as a repetitive story mode, and how unlockable characters are a terrible idea. In general, though, I think that Yahtzee falls into the audience defined as "the large group of people that Brawl just plain old isn't targeted towards", which includes most people in this thread. I find the mindlessness of it all rather engrossing, and what the core gameplay consists of is extremely well done if you're looking for that sort of thing.
What threw me was the comment about button mashing. No offense to many people here, but if you gather four people together who completely suck at Smash Bros, the best masher is definitely going to win. So far, though, I have never once seen a masher do well at all against a more experienced player.
As for being "that guy", that certainly applies to a two-player match (in all games), but I have data that proves otherwise in four-player matches. I went and gathered three other people who have never played Smash Bros before, or many games at all, really, and played against them in a Brawl. I won hands down, but this seemed to do extremely little to bother them, and they had a great time.
I think the key issue here is that Yahtzee just falls into a different crowd than what Smash Bros is aimed at, as I've said before. And it is this, of course, that makes a horde of delirious fanboys spam his mailbox with hatred, but in all honesty, anyone who flies into a rage over a Yahtzee review isn't worth that much to society.