Google is quite effective when searching AN - just add "inurl:atarnotes.com" or "site:atarnotes.com" to your search query (and then you can also refine your search better with all of Google's other search operators). The 'google' option on the AN search does that automatically (add on "site:atarnotes.com" at the end)
I tend to use that more than the AN built in search, although Google isn't as good with filtering the search queries with the forum-specific stuff (usernames, by board etc.), naturally the built in search on AN is better for that.
The policy on repeated questions that they had on that link you posted seems to be a bit strict, I think there is quite a bit of merit to repeated topics - you get different opinions and the discussion might turn in a way that it hadn't before. They aren't really the type of threads that you're talking about (if you look at the maths board for example, it's not surprising to search one of the questions and find that it has been asked a few times in the past few years).
The type of threads you mentioned, I was under the impression that was what this board was created for:
Technical Score Discussion. Those types of threads could also be reduced by having a general, stickied thread that explain how scaling works, how study scores are calculated etc. I'm pretty sure this idea was suggested somewhere a few months back - and I reckon that a guide like that would be a lot more effective in reducing the problem than merely moving the search bar ~250 pixels down and whatever pixels left.
Not all users are too bad with the search function either, seeing that a lot of old threads get bumped often by new users.
edit: fixed typos, sentence flow