If a large % of users have the problem you're trying to solve, they might rather abandon twitter altogether than going to yet another tool to try to fix it. And if not, you're building a product for a (by definition) niche audience. Is going for a niche audience indeed the plan?
Interesting point. I think Twitter can be overwhelming in the way that the internet can be. People didn't abandon the internet just because it was hard to navigate. They turned to Google.
I'm currently working on the same exact problem: http://slipstre.am/