Wouldn't the F/O's screens lost power with the double engine failure? That would dictate that the Captain would have to fly as he'd be the only one with flight instruments.
According to the NTSB briefing, it was the F/O's leg and the Captain took control when the engines quit.
Nothing indicates YET that electrical power was interrupted by the engines (APU on?) shutting down.
A320-wise though, you are correct about the load shedding qualities of the right side PFD, etc during electrical failures.
This came down to judgment from a trained, seasoned and experienced professional who was faced with some of the following questions in about a 90 second period.
**The following is a dramatization for illustration purposes only...**
Heads down monitoring and BOOM!
What's happening?
What happened?
Where are we?
The engines are spinning down.
We're not climbing.
I'm going to take the controls.
Pitch up to maintain altitude. Look for options in the cockpit and outside.
Get the F/O on the checklist/memory items. (I don't recall any for a dual power plant failure in an A320 when I flew it).
Where are we going?
We're going down.
Can we restart the motors?
What's my airspeed?
Can we make it to LGA/TEB?
I'd rather ditch in the Hudson than land at TEB. (Can't blame Sully for that!!)
Should we try for an airport at all?
To ditch or not?
How's that checklist coming?
Ditch it is? What configuration for gear/flaps?
Where's the GW bridge? Boats?
Man, this feels weird.... fast. Not enough drag.
What's the wind direction?
Announce the "Brace" sign.
Aim for the left bank/right bank?
How's my speed?
Too many variables....