I leveled engineering a few months ago and never declared a specialization because I guessed that Blizz would later introduce something cool that required a specialization. I know it's not hard to change specializations, I'm just saying Blizzard is semi-predictable.
Anyway the winning specialization will be the first weapon that drops when I have enough resources to to obtain a Primordial Saronite and/or bullets because I already have 3 stacks of Eternal Earth collecting dust in the bank. :)