Brightness changes too frequently after I updated to 4.2 I have a Nexus 7 and after the update to Android 4.2 setting the brightness regulation to auto I noticed that it changes way more frequently than it used to do in the previous version of the operating system.

Is there a way to have automatic brightness regulation less aggressively?
Unfortunately it is a known bug introduced on Nexus 7 with Jelly Bean 4.2. In previous version 4.1.2 auto-brightness was criticised as slow in reaction on light changes and now in 4.2 it is just opposite, over-reactive. From one bad to another bad. But I agree with you that even previous not so good behaviour was better than what we have now. Someone cure it by sticking small semi transparent tape over light sensor. But it is only temporary and ugly workaround, we can hope for correction in the next version, or downgrade to previous 4.1.2 version.