It takes time to understand what new media are for. Real, human-scale time, measured in years. The inventors of the telephone thought it was a B2B technology, didn't really grasp that everyone was going to have a phone in their home and use it to talk to relatives. The inventors of the phonograph, amazingly, thought of that as a business technology as well, for recording memos and stuff.
Twitter et al are in their infancy and are still growing. They get new users all the time; the new users happen upon different aspects of the tool and use it differently; some uses are ultimately better than others. It's the blind men and the elephant, except that the elephant is the size of the Library of Congress and there are seven billion blind men, two thirds of whom have yet to touch the elephant.
I, for one, don't have so many problems with Twitter, but that's probably because I use it differently from others. Let me offer some suggestions:
If you find that you feel lost because you no longer remember how many of the people you follow on Twitter are still alive you need to follow fewer people. I follow 97 people. Even that may ultimately be too large, although most of those people are very quiet, so I can probably keep growing it, especially as the client software gets smarter.
Remember that Twitter is RSS for humans. It's Delicious for non-nerds. It is for exchanging links, not ideas. If you have an idea that can't fit into 140 characters write it down in 2000 characters and then tweet the link.
Of course, Twitter can also be used to exchange ideas that are not worth more than 140 characters. Sometimes these Tweets are short because they are poetry. Sometimes they are short because they are stupid. Follow the poets; unfollow the stupid. Just because people are shouting nonsense doesn't mean you have to hear them. The Internet's soundproofing is very good.
Speaking of Internet soundproofing, signal-to-noise, and maintaining one's sanity: I don't follow hashtags. Like, ever. I'm not quite ready to pound the table and declare that hashtags are never going to work, because they're eventually going to be nothing but SEObots retweeting other SEObots in a vast, roiling AI botwar, but I for one don't miss them. Important things get retweeted by your followers or echoed in some other medium.
If someone's Twitter feed is not a net win you need to unfollow them. This can hurt. I kind of like Roger Ebert's Twitter feed, but the guy does. Not. Stop. My feed is like 85% Ebert. And almost everything he says is interesting, or could be interesting, but I'm not suffering from a shortage of interesting things, and he's drowning out the quiet folks. I need a Twitter client that has better stream management. For example, it could throttle access to my main stream: Ebert gets X tweets per hour on average into my aggregated stream; to see Ebert's full stream I need to click on something.
Speaking of which: I know there are ten thousand Twitter clients already, but there will be more. Client development is also in its infancy.