While I don't want to armchair quarterback this too much, I'll just add a small point (yes, I know that's a contradiction). My disclaimer is the pilots of this flight are the only ones who fully understood the nature of the situation and made decisions based upon their knowledge.
But, in my experience, the complete loss of electrical power isn't necessarily a reason to add a few knots of speed. I don't know the 757 systems at all, so I don't know if the flaps are hydraulic or electric. On the 2 models I fly, the flaps are electric, but we could lose all 3 generators and they'll still work above 145 kts on the ADG.
22R is a fairly short runway, especially if you add the 9R LAHSO. Maybe this wasn't the best choice of runway for this occasion. I just find it odd that they apparently waited until on final before declaring an emergency.