Here's a simple way to improve YouTube. Turn off comments.
I have never once, as far as I can remember, read a YouTube comment that was in any way, insightful or provided meaningful information that wasn't better obtained elsewhere. It is a cesspool, and the people who are complaining about needing to login to G+ to leave a comment frankly largely intersect with the set of people who are the problem.
Honestly, if logging into G+ bothers you, you probably are the kind of person who "shoots from the hip" and doesn't put a lot of thought into your comments anyway.
I don't believe the G+ comments on YouTube are about the idea of real identity being a check against racists, assholes, douchebags, and other comment archetypes. That has failed for Facebook comments and so has up/downvoting on YT. Instead, I think it's about filtering based on social network sharing.
Simply put, if someone shares a link to your video somewhere with their circle of followers, the external thread that develops outside of YT, within that community is likely to be more coherent and cogent, and that will be surfaced in the YT comments especially if you have social affinity with that person.
Think about it as a kind of comment federation. What if every YT video that has been linked from HackerNews stories surfaced the HN comments directly under the video on YT if you were in fact, a HackerNews user (had a login). Don't you think the HN comment thread would be higher quality than the general YT audience comments? That kind of federation is technically not possible today, because we don't have a standard spec for comment upstreaming, but because Google owns G+ and YT, they can do this kind of integration.
The reality is, comments from video reshares from people you know, who have small circles of followers, will be higher quality. Someone with 10,000 or 100,000 followers however probably will exhibit the same problems because the probability of bad actors rises with quantity. However, at least you can control this by filtering who you follow.
There's a general purpose derangement going on with respect to G+ that I just don't get. I don't like Facebook, never have, I barely ever log into it. I don't like social networks in general, I like _interest networks_. But I don't throw a hissy fit when most of the sites on the web force me to either create an account, or login with Facebook. I just login with Facebook and go about my business, denying most of the permissions it wants from me. It's really not that big of a deal. I don't use FB, but it is not a burden on me personally to use it as a single sign on service.
The reason why I use G+ is similar to the reason why I use HN or Reddit -- the communities. Simply put, there are more interesting, tightly knit, communities with less annoying, disruptive people on G+ than there is on FB. Maybe that's elitist, but that's the way it is. Perhaps it's the advantage of having less users, less adoption than Facebook. There's merit in being a so-called "Ghost Town", in that anyone willing to live there is more dedicated to the town, and less willing to take a shit on it.