First, I apologize for the frustrations you have had with searching the forums.
The search function has been a long standing weakness of the site. It's been discussed many times in the past, and using it is definitely more of an art than a science. A few notes:
• The Google Search option was added to the Search page as a way to include the other pages of the site (such as the weblog) in a search for those visiting/searching the site for the first time who don't visit via the front page.
• The search is limited to 4 characters or more as a trade-off for faster searching. However, the "underscore" work-around does work, and is described on the Search Error page if you search below the minimum characters.
• Since adding the "Search this forum" form at the top of every Forum Topic page recently, the number of duplicate posts has decreased noticeably (even as the number of visitors to the site has increased) -- so it does work in some respects, but obviously is far from perfect. If you'd like to search like the admins (and power users?) do, use a single keyword in that form at the top (or bottom) of the message topic listing in the relevant forum.
• The search would be overhauled when/if the site gets it's overdue redesign. Since that's a long-standing broken promise, I won't make any predictions on a time frame. Unfortunately, many different circumstances have delayed that work for some time now.