As animuson notes, folks see bounties by the amount of time left, with those closest to ending at the top. 434 questions is a lot to drill through, but tag filtering takes the list down to 20 or 30.
The problem is, if we shorten bounties, we make the list churn even faster, which means your questions would stay at the top of the (default / unsorted list) for even less time than they currently do. Alas, you'd probably get the exact opposite of what you want.
What has occurred to me in the past (and again just now while I was poking through the list) is that it's a little .. wonky to discover that there are featured questions in the tags that I know something about. I first have to realize that the tab setting at the top is 'sticky' (it will stay on featured) before I realize that clicking on a tag drills down into it.
We have some navigation fixes (a pretty serious effort, actually) in the works, and this is definitely an area for improvement. I'm also happy to look at any feature request that proposes interesting ways to get featured questions in front of people that can probably answer them more efficiently.
You've identified a problem, but I'm worried that the proposed solution might actually exacerbate it. I really think it's an issue of visibility and antiquated navigation, not so much an issue with the length of bounties. It's only a major problem once you get over 50 or so questions on the list.
Declining this, but I'd love to see any more ideas for giving those questions better visibility (wonky navigation aside).