IMO, the whole engine management should be revised, not only for WEP. The temperature should start raising even below our current military setting, and it should also be depending on the speed for air cooled engines. Crossing the "red" line does not imply any increase on the temperature raise rate, but it increases the chances of breaking the engine.
Only planes with some especial emergency power switch should have a WEP switch, any other plane should have just max MAN attached to the throttle control and max RPM.
Currently, in most planes we have a range of powersettings that can't be set between what we call military and wep.