Actually in my opinion, the way it is right now, is quite good.
Thinking of a new user here, not being here before and searching for an answer. If the thread has 1000 replies, how long would it take for him to find the answer? And also, I don't think that a new user will be looking for a navigation bar to sort for "Answers"
or something like that. I think a new user wants to find the answer as quick as possible and in this case, it is good to drop the answer right after the question.
The following is my signature:
Powershell Programmer & Advanced Lua Programmer
Location: Switzerland
Beside that, whenever you see a reply, you think is helpful, mark it as "Helpful"! And whenever you see a reply being an answer to the mainquestion of the thread, mark it as "Answer"
(if you opened the thread).