Site search control and Google issues

Hello all,

Our Community recently had to deal with a rather annoying problem with Google.

To have it make some sense i'll first describe our situation:
We have a closed-off part of the Community for archived topics. We created this as the Site search of InSided was less accurate than Google and most of our users enter the Community though Google search. As will probably be the case for many of the Communities here.

Unfortunately Google started to really delay on removing content from its results, which resulted in visitors ending up on 403 pages.

We remedied this by building an open archive so everyone would end op on a normal page.
Off course this does not change the fact that most of our visitors come from Google and now end up on pages that do not give them the answer they want. One way of solving this is by linking a lot to topics that do contain a relevant answer and by having the site search work in finding relevant topics instead of archived ones.

This is where my idea comes in.
Right now we have very little control over the Site search or how relevant they are to Google.
For this I think three things can help.

One:
Adding site search controls to the back-end of the community. Let us decide what should be the most relevant at the top of the search results, like answered topics, last responded date or Sticky topics. Then, let us share our findings and settings with each other on this forum. This way we can also help each other out in defining what works with each different way of work per community.

Two:
Adding an option to every sub-category (in the Forum structure settings) to ex- or include it in the site search.

Three:
Adding a Sitemap from InSided side to give content a search rating based on relevance.
For example, everything in the 'said archive' gets the lowest rating. Making Google prioritize newer, more relevant topics.

I don't know if many of you have had experiences with the above, but I'm very curious if you have had them, and your opinions on the above all together.

Cheers,