Interesting read:
http://www.autosport.com/news/report.php/id/87761
I must say it corresponds to what I was thinking. Just this morning I was having a conversation with some F1 enthusiast colleagues about the slightly odd season Merc is having.
They started not all too badly. Then as soon as the development push really kicked in and they had many things to test, their form went backwards (remember our mantra of the Merc updates never working). Now that they're seemingly just trying to get the best out of the car things are looking up a bit more.
Something similar happened to McLaren last year (I was a fun until Merc got their own team - don't judge, no one's perfect). I recall them developing the ever loving --- out of the MP4-24 with little to no effect. Then for a few races they just tried to understand the car and from then on things were going considerably better again.
So really, I think we're seeing the same happening to merc. Hindsight is 20/20, but I daresay if they had done this a bit earlier in the year things wouldn't have looked so desperate compared to the evil triumvirate up front. I'm not saying they would have been contenders. But Renault would likely not have been such a threat.
As an aside, I'm really feeling very optimistic for next season. The momentum seems to have swung in their favour and experience tells me that counts for a lot. MercGP are seemingly looking to strengthen their technical department with new recruits (the williams guy and michelin guy comes to mind) as well as drawing knowledge from the mothership, Daimler (they have had daimler tyre experts assisting them as well, I read somewhere). At least they look like they're trying to do something about their situation. Go MercGP W02. Achtung Baby...
Edit:
They even appeared to get their WTF-duct working now. Touch wood...