I'll consider your suggestions carefully before I make any upgrading.
Let's me introduce the current functions related to your suggestions.
Currently there's a "Historical Zone" for those "old" discussions. When you search the forum, it's in the current area, but in the result window there's a link where you may search the same thing in the Historical Zone.
Another design of this forum is the "Hit List Zone" (精华区). Any discussions worth reserving is in this zone. You may still read specific "board" or "category" in the Hit List Zone, so that you may find what you need in a straightforward way.