I must admit I'm not the sort of guy to rant much. At least when it concerns about the content of a video game. It sucks when some elements from previous games are removed on a sequel, but in the end, it's just that: a game. If you're not having fun with it, what's the point?
More often than not, the new content makes up for the removed stuff. It was the case with Brawl when I found Mewtwo was gone and it's the same thing for this game.
I tend to vent my frustrations about other people, though.
Also, rule of thumb; If you don't enjoy it, don't play. It's okay to explain why you don't, provided you at least played the game so you have legitimate reasons to not be happy. I hate Unleashed, but I played a lot of it as is so I have reasons to. I love 06. I played tons of it too.
Then again, I have a weird selection of games I like and dislike. And it entirely depends on many factors. For me, Quest 64 > Brawl. However, that doesn't mean when it comes to a review based upon many details of the game(I tell it like it is, presuming I can really play well through the game to give a detailed review), my preference will not determine my review entirely. I have given Quest 64 a 3/10. Brawl I'd at least give a 7/10 minimum. I don't think enough reviewers tend to try and remove their bias a bit in order to give all information at a neutral glance. They are opinions, but still. Tell the good and bad as equal as possible. Let that determine the review overall, not your direct bias.
Same reason why I would love everyone back in Smash 4 via DLC if possible. Even if I don't like the character at all. Is it relevant? Nope. Some do, which is good enough for me.