I was using the AP spec pre-1.2 and felt I was doing great progress and could almost match the overall damage of a Pyro spec. However, since 1.2 my effectiveness as AP had decreased drastically due to constantly dieing. The problem with PFT is that you have to penetrate the enemy lines and stay stationary for 3 seconds which makes you a target and with the changes in 1.2 I end up dieing in seconds.
Because of this I went back to a Pyro spec which allows me to hang back a bit and I manage to survive much longer now.
I've read a lot of statements that a AP player can go up against 3 enemies and kill 1-2 of them before going down. Either I am a terrible player or those 3 enemies are undergeared and underskilled. If I have 16k HP and 3 players dealing about 2k damage per GCD will bring you down in 1.5*16/(2*3) = 4 seconds. As they likely have at least one stun between them there is no way to survive those odds.