Just to follow up on this. I upgraded a few weeks before to Ubuntu 15.10 and it looks like this bug is completely fixed.
It has the following kernel: Linux 4.2.0-18-generic #22-Ubuntu SMP Fri Nov 6 18:25:50 UTC 2015 x86_64 GNU/Linux
Wifi works stable without any additional tweaks.
Happy that this was fixed, thanks.
Just to follow up on this.
I upgraded a few weeks before to Ubuntu 15.10 and it looks like this bug is completely fixed.
It has the following kernel:
Linux 4.2.0-18-generic #22-Ubuntu SMP Fri Nov 6 18:25:50 UTC 2015 x86_64 GNU/Linux
Wifi works stable without any additional tweaks.
Happy that this was fixed, thanks.