The noticeable improvement will come with the integrated graphics code. Laptops will get the more powerful "GT3" version of the graphics core. Not sure if it is called the Intel HD 4600 or HD 5000. Not sure what the exact performance increase is compared to the Intel HD 4000 though. Some people speculate between 50% - 100%.
The CPU core will likely not improve much until Broadwell in 2014 which will be based on the 14nm die process. That allows Intel to reduce power and also increase clockspeed. I am sure they will also tweak the overall performance of the CPU core architecture as well.
You are correct, Intel is focusing more on mobile device this time around. However, the mobile device they are focusing on is not the laptop. It is the tablet.