I have used Gmail almost since the service started, and I would hate to lose conversation view. I subscribe to a number of mailing lists, so I frequently read deep-threaded conversations. I have never had the problem you speak of. Finding the correct person to respond to is trivial, and if you need ways to find the messages you haven't responded to, there are a number of options.
I could see there are times when switching to non-conversation view might be handy, but I can't say I have ever wished that I could do it.