The "social search" experience with Google+ has been underwhelming so far, to say the least. The problem is largely one of relevancy: Most of the Google+ stuff that gets dragged into my searches is completely useless and not relevant to the search at hand. (I would guess because Google's trying to make something meaningful out of often loose connections between me and other people.)
My Gmail, on the other hand, is a world of almost nothing but relevancy. It contains basically all the things I talk about every day — with the people most important to me — stretching back for the last several years. Along with crucial data, like flight numbers and doctor's appointments and restaurants I might go to next week. If Google can't make relevant search results out of that — the very fabric of my conversations — it should probably get out of the social search game entirely.
Oh, two other things have changed in search — again, for the better. It's like good ol' Google. Search is also now listier: