I also noticed this. I normally use the server browser to find games. I was looking for a TDM game and only found 4 matches in the US regions. I found this very disheartening and decided I would widen my search to include full servers, this returned 45 pages
of servers. However only 4 of them were not full! Later in the night while playing Rush with friends we continually had half full rooms, kinda frustrating. Hopefully this will pass as people who were busy trying MW3 come back.