Often a chip will be available in several different packages. Sometimes QFN which has a thermal pad, and TQFP which has no thermal pad. The justification for the thermal pad is that it helps conduct heat away from the IC. If this were the case, then why doesn't the TQFP need the thermal pad?
The reason I'm moaning is that the thermal pad gets right in the way of the layout. Tracks and vias can't be placed under the device (except in some cases), making fanout tricky in space confined PCBs.
Is the thermal pad just traditional, or is there a good reason I'm not aware of?