Well,
the goods:

+ That is an Atlantic battle oriented release,
+ You have to care more for your crew, more FRP elements,
+ There will be no anti-alliancing issues like SH4 this time
+ They promise a more "living" world around us with AI subs and Bdu
+ Better Damage control with animations
The bads:

- Everything comes to an end in 1943
- Only one type (VII) of sub is available
- You have to personnaly travel in the sub to use/command features (no more shortcuts)
- No direct wolfpack coordination
I wonder:

* If they will overload and bogg down my GPU with hefty graphics
* If they will f** my pc with a damn security prg.
* If ridiculously shooting aircraft down like flies is corrected with this version
* If they made use of wonderful add-ons and mods community developed for SH3
* If i will be able to control more in base options (upgrades, crew mwmbers, resting time.. etc)
* I hope this will be nothing like SH4 but more like SH3.