Kosmo,
We fly in a hot environment and have seen a few overheats from time to time. A difference of +/- 2% is within limits for the setting of takeoff thrust but I never liked the idea of messing about with thust at that stage. If it predictably overheats then as as far as I am concerned there is a problem that needs sorting and I would rather the company spends the necessary wonga to rectify the prolem or take the aircraft off the line.
For the e.g. 737 it doesn't mention anything about landing at nearest suitable airport, if the engine subsequently stays within limits. Hence, you can continue.
True, but how much and how long would be a consideration. The Boeing AFM contians a bit more info. Regardless, if no engineering down route I would defo return.