Most things I watch are 7-10 minutes. I have a healthy subscription list of new content almost daily. I watch minimum 30-60 minutes of YouTube a day, more on weekends and holidays.
Additionally YouTube already has my payment information and I already use it to rent movies (via the Play Store, which plays on YouTube).
I don't use AdBlock because I want to support the people who I watch. If I block the ads they have to go get a job and they stop producing original content which I enjoy watching.
I won't claim I would definitely get a YouTube subscription, but I'd consider it (devil is in the details and all that). If it meant I was funding people who I watch daily better (a la Reddit Gold) I very well might.