In the critical phase of take off wouldnt an early indication of engine problem be useful, therefore monitoring EPR would show a problem earlier than a reduction in fan speed N1 and allow direct action to be taken earlier?
As was mentioned before as long as parameters are set and agreed to before t/o roll then any deviation from the norm is an indication that something is wrong.
Technically I'm not sure if this is why EPR is still used but it would make sense to monitor the core function which at the end of the day is driving the big fan around to get you airborne.
------------------
Its life Jim, but not as we know it!!