Since the number of Immortals is growing and many are going unused, please allow 2 per team instead of just 1. For example the new Immortal Byblios is not as powerful as Ossifer, so in Ancient Khet my Byblios will go unused, unless I can use 2 in a team. The Immortals are not all that extremely powerful, and if not used in their own region are often quite weak actually, so I don’t see why we cannot use 2. If need be restrict it so only one does double damage in its home region.
Otherwise releasing more Immortals is just pointless.