For me, it's what I take from the language of the update. The ship's maneuverability is talked about it terms of getting more hits with torpedoes and it's use after the war is over, not avoiding damage. I understand the argument you're making, and where it's coming from, but I don't agree it's enough of an issue to warrant the cost.
[X] Two Engines (Low Maneuverability, 23 -> 27 Industry)
I can't speak for other voters but the reason I'm voting for two engines is because I want to splurge on phase cannons.
I want this thing to be made out guns! Battleship go PEW PEW PEW!