Exactly. Facebook should be for friends and people you actually know. Twitter works best if you follow people with shared interests (professional or otherwise) that you may or may not actually know in person.
If you want to follow many people you can't follow people who post frequently.
I think that's reasonable; surely professional tweets can be restricted to a dozen a day.
If twitter makes it possible to prioritize tweets that will change. But as long as everything is time-ordered, high-frequency tweeters interfere with my ability to follow high-priority tweeters.
No. If you want to follow many people you can't follow people who post frequently. I happen to be able to (TweetDeck helps a lot). It's a tooling problem, not a service problem.
Isn't it relevant that you need to use third-party tools to make Twitter usable? The concept of Twitter may live on, but I think we're all just waiting for a better implementation.
Heck, they had to buy another company just to provide search for their own data!