I don't think destroyers are a good idea; they can't dive for enemy airplanes.
Besides, DC was a separate game from SH. Complaining about SH5 not having DDs is besides the point; there never were controllable DDs in any SH game.
And I'm sure there will be German voices in SH5; they could always just recycle the ones from SH3.
Imho, the best news is confirmation that they're using a new engine. Sub-on-rails? Gone. Crew remaining on bridge during dive, or suffocating after surface? Gone. Bowplanes that inevitably got stuck in up or down position? Gone.
All the minor things that annoyed everyone, gone. Really excited.