I too dislike the new search. My use case used to be as follows:

- Open the forums
- Do an advanced search for posts by my username

This would provide me with a chronological list of all threads that had recent activity... Even if they started two years ago. I could also see if the last poster in a thread we me - If it was, there wasn't any point in opening it. If it wasn't me, then there was new activity, and I'd open the thread and read it.

It would also provide me a convenient list (on the right) of the forums I'm most active in, and I could open each forum.