That's not really true about Bahamut. You just used Dreadwyrm Trance and waited 15 seconds, or until casting Deathflare, and then summon Bahamut. It only felt rewarding because there was nothing interesting happening in-between. It was still fun, cool and my main, though. It just needs 3 more summons now and Aetherflow abilities to go with it and it would feel like it has a ton of things to do and refreshed. It does more now too than it did in ShB.