To me it doesn't matter that it is a no follow link. A link from Wikipedia is no follow as well, does that mean it should stop you from trying to get that link? Hell no!
I don't think there is a very good definition of what makes a good tier 1 link, but for me it's simply this. It needs to be a link that you can have control over. It means you can have the power to remove it as and when you need. This is important so that you can pull out that link if you know it is not helping you rank. Web 2.0s and PBNs give you that power. YT is great as well as you can always remove it later.
This is in contrast to stuff like GSA spam. Once you have built those links, you can no longer remove them. Which is why many on the forum would suggest building these spam links to Web 2.0s, because if shit hits the fan, you can always remove the web 2.0 links.