[Sombre]

This all sounds excellent. Let me know if there's any way I can help. I especially like the idea of 'fixing' stuff which in vanilla doesn't really make sense.

I think it would be wise to avoid making death too strong against UW though. It's already a very powerful path and if it's actually giving you better options to go underwater than nature, air and water, that feels very wrong (which it might with stuff like fully amphibious ghosts). I believe the way to counter this is just to make sure that the N summons, W summons etc that are going to go underwater are comparably good.

I also think more sites should be added, coded to appear on coastal provinces, that give decent indy troops for invading the seas. This is especially helpful on NI maps, but also on regular maps it would be awesome to be able to take the coasts and get amphibious troops of good quality (better than mermen and naked shamblers) and inversely, it would be more incentive for the water nations to actually try and hold the coasts.