The Nashville Baron was only 3 miles out...that puts him around 1000'. That is not enough altitude to recover from a unusual nose-low attitude, let alone departure from controlled flight. The engines' operating status has not been released so there is no reason to draw any conclusions in that regard.
During any instrument failure, one can expect a degrade in situational awareness - something we all must fight, especially during IMC.
As far as a critical engine, both the Baron 55 and 58 have the left engine as critical.
But thrust alone does not make one engine "critical" for myself. In several Apaches I've flown, the left engine also contained the only hydraulic pump, so loss of the left engine meant not only flying was a pain, but lowering the gear took 52 pumps - alot for a quick return in the pattern.
What drove, no inspired me to fly a twin was not the extra engine (although it is nice over the mountains) was the extra alternator/vacuum pump that is spinning on the other wing. Those are handy at night.