Yeah N1 is definitely easier to calculate, since it's kinda a Tachometer by design... and yes, EPR is the more accurate of the 2.
An innovation that I've seen (ig in the A350) is the presence of 'calculated thrust' gauges which are meant to be more intuitive to use.
So, the PW4000, if given inadequate bleed... would give you a nasty Hot Start or the FADECs would auto-cut the fuel and turn the start into a Dry Crank Motoring phase?