Originally Posted by
Zenion
So, the thing there is, how do you think that works, mechanically? I can only think of a couple of zones where effects are applied to locations, and that feels very much like something that had to be baked into that zone specifically. To be able to do an area effect that can just be arbitrarily dropped anywhere, there would need to be a source. Whatever that source is will need to be attached to whoever created it, in order to handle cleanup - as fun an idea as it is to have an effect that lasts after you zone out, that would have all sorts of disastrous potential given the overall fragility of FFXI's code; your effect needs to be automatically culled if you zone out or are defeated.
There's basically one system presently in place to handle that sort of thing: pets. It would take up the pet slot. I don't know why a luopan counts as a pet (besides making it easier to fit multiple jobs on one piece of gear) but it does; this would almost certainly have to be the same situation.
You could wave it off by saying Bahamut is just that much, that you need to take time to recharge before you can summon again, but I just can't see a way that you'd get a lingering area effect without it having to eat the pet slot, in the game as it's presently structured. I don't know what the FFXI source code looks like so I can only speculate, but I think this is probably also the reason we don't have beastmaster or puppetmaster trusts, and the summoner and geomancer ones barely leverage their job features. Trusts aren't quite pets, but they tie themselves to their owner in such a way that having them generate a pet would probably make that pet count as the player's one and only available pet? Which is... a weird problem, on the surface, but programming-wise I can see exactly how it could happen.
Getting a little off track now but TL;DR I don't think Bahamut could have a lingering after-effect without either a non-trivial change to the game's code base (creating a new pet class that doesn't count as your pet, similar to your adventuring fellow, or copying Reisenjima's darkness spheres to every zone and instance where Bahamut could potentially be used just in case) or blocking the summoner's summoning.