I can not confirm your statement as I am running a plasma build that is neither DPE efficient, nor build for face tanking. It actually is the problematic hybrid build and it works really good I have to say. Even in wing fights and against misisles my burst hybrid usually deals more damage against these face tankers.
Why? Because even though having less DPE, plasmas deal raw damage and therefore increasing their DPE. It still isn't suited for face tanking with a 4-0-2 configuration as WEP DOES NOT SCALE LINEAR! Heat generation and and energy distribution scales almost the same way SYS does. The only exclusion being ENG with it's passive effect. However, I do not think that we need even more agility than we have now. Look at these 750 m/s ships with their enhanced thrusters. They are so fast and can perma boost so nothing can catch it.
That said, I must disagree as I have evidence of face tanking that lost against 0-2-4 configs. I even tried out face tanking myself and I did had trouble against burst loadouts, especially when it comes to railguns or frag cannons and plasmas.