I'll be hesitant to purchase it until I at least get a green light that the current major mods have been upgraded or verified to be compatible with the Add-On and I agree that we are looking at several months for that to happen.
I'm kind of interested in raiding some allied convoys in the Indian ocean. Being able to call in surface and air support will give it a new twist. It will keep the surface ships occupied with a greater threat while you line up for a good shot.
As for the Atlantischer mod, even if we started out with missions in the Med and off of Africa, it would be a good start. The nice thing about SHIV is that they pretty much mapped the entire globe. We already havve the real estate and it's just a matter of generating traffic with the correct ship models. I guess the modders will be importing a lot of models from SHIII.