As I recall, the only tactical difference is that subs in the WW2 game have a slightly longer range (21 APs versus 18), which makes sense given technology improvements. Since sonar was a WW2 era invention, I wonder if ASW tech should be as strong as it is in the WW1 game? A slight shift in the balance between Advanced Subs and ASW tech would increase the survival rate of German subs.
Most of the differences are the strategic ones you have already listed. But you overlook a major strategic difference with the WW2 game - which are the NM hexes off the British coast and the possibility of shutting down British ports. That strategy does not exist in the WW2 game and it makes the attractions of investing in sub capability much greater for the German player in WW1, even if you have to keep building new ones to replace losses.
So I went and compared the subs in the editors.
WIE: 20 AP NA:5 ND:5
WW1: 18 AP NA:3 ND:3
WAW: 16 AP NA:5 ND:5
I'm assuming AP is adjusted to map size.
Conclusion: Since WW1 subs were the most deadly of all eras NA and ND should be raised to 4 or 5.
I've been pondering the same issue (threads like this are always very useful ) and in the WWI game the subs have a naval defense value of 0, whereas in both WW2 games it is 1.
Increasing this to 1 would therefore help them survive attacks better.
With Maritime Bombers, they can currently upgrade to level 2 in Naval Weapons and 3 in ASW, which with hindsight seems rather generous. The next question to consider is therefore a more appropriate level of upgrades.
Ah yes did not notice this one! Thanks for considering Bill! My only other recommendation would be for all of the games. Any ships with an ASW of 0 should not be able to attack subs and reduce supply. For example preventing players from using Pre-Dreadnoughts, Dreadnoughts, Battleships, etc., from attacking subs. It makes complete sense anyway. This would get rid of the ability to use the entire navy to reduce the supply of a sub to 0 and destroy them all so quickly...
< Message edited by Tanaka -- 1/16/2021 6:48:44 PM >