I know that forming a Federation with AI empires is a bad idea. No need to remind me. 
First the ability to keep the federation presidency and control of the fleet makes federation play with AI empires much more fun to me.
The energy tax of 15% seems rather excessive. I dunno how much you get out of the free commercial pacts as I have not found the information yet but even AIs on GA do not seem to give much. You can also form a federation with machines which means you get nothing in return.
The federation fleet cap max. of 500 makes the entente coordination tradition tradition with its +100% federation naval capacity contribution effect nearly
useless as you will hit the cap anyway. That tradition should get a different effect imo. Maybe it should increase the max. cap by 100 per member who has the tradition(so a max of 1000 for a 5 member federation when every member picks it) or give you the ability to build gateways in allied territory.
I also think federation members should get free research agreements.
First the ability to keep the federation presidency and control of the fleet makes federation play with AI empires much more fun to me.
The energy tax of 15% seems rather excessive. I dunno how much you get out of the free commercial pacts as I have not found the information yet but even AIs on GA do not seem to give much. You can also form a federation with machines which means you get nothing in return.
The federation fleet cap max. of 500 makes the entente coordination tradition tradition with its +100% federation naval capacity contribution effect nearly
useless as you will hit the cap anyway. That tradition should get a different effect imo. Maybe it should increase the max. cap by 100 per member who has the tradition(so a max of 1000 for a 5 member federation when every member picks it) or give you the ability to build gateways in allied territory.
I also think federation members should get free research agreements.