I’d Like Your Opinion On Blog Carnivals

Here's mine.
There are a lot of blog carnivals…I mean a lot. There seems to be a carnival for every interest. Every interest, but one – there's no Carnival of the Carnivals. And that's probably a good thing.
Carnivals are an interesting concept – a group of bloggers submit articles, a rotating host publishes links, links are published back to the host, and readers are treated to a best of. Win-win-win.
Kinda.
The problem is few carnivals are truly a best of and few who submit posts publish a link to the host.
Some carnivals have host guidelines that limit the number of submissions – an attempt at using a velvet rope to raise the quality of published posts – but it rarely works. While it's nice to say there are no bad posts, it's untrue. There's a lot of poor writing and senseless rabble in the blogosphere. And I'm not just talking about my posts.
All in all, I'm not sure I like blog carnivals. Although I submit posts each week and plan to host a couple in the future, readers and bloggers don't appear well served. It's an interesting concept, it's just overused and under standards of quality. Maybe that's what the Internet and blogosphere are all about.
What do you think?
If you read blog carnivals, do you find them valuable? If you don't read blog carnivals, why?