No canoncially we did everything on Azys Lla alone. So we took down Regula, two ascians plus their combined form and Thordan and his knights alone. (We were only traveling to the flying isle with our scion buddies and they split away from us before the dungeon. We simply cant have other people with us at that time since we are the first to arrive there thus nobody could even just teleport to us. And the lore book confirms it too.) Regula is later than also killed by Zurvan while we kill Zurvan too.
Thats exactly the problem I have. SE already introduced so many godlike impossible looking enemies which we defeated (heck even if we had adventurers on our side in the new 24 man raid..defeating this version of Diabolos is one hell of a feat [I learned]) so I just cant believe that there will be suddenly even stronger opponents especially if they are still mortal. I mean Thordan was the strongest primal till now and was fueled by the eyes (+Lahabrea), lots of prayers and even the Warring Triad and we defeated him alone. What kind of being will there be at 5.0? I wished that they had started the first expansion a bit slower. Instead of having such enemies they could have gone more about man versus dragon. Let us be saved by Hydaelyn against the Ascians instead of killing them off so easily. Let us defeat Nidhogg but only with the help of lots of people and dragons.
With that solution I would have understood that we are powerful but just still a normal mortal. Then with 4.x they could have given us enemies like Zenos that thrashes us. Overcoming him seems way more natural that way. Then with 5.0 we might destroy the first few Ascians on our own and maybe have some enemies like Diablos. And later we could have enemies like Thordan. This would have made the whole journey more realistically and still way more enjoyable and logical to me. Because you are 100% right, who are we going to defeat later? What power do they have to own to even make sense that we will not just mop the ground with them? Because right now after everything that we killed it just doesnt make sense that there is a mortal single person alive that will trash us. (Because this does not look like a stalemate)
Short version: They have made us too powerful too fast in the recent expansion thus any future expansion needs quite the enemies or strange reasons for us to loose against mortal people.
[Still good to read that there are others that find this point a little strange]
I would find it nice to have a choice but I cant truly believe that we can either choose one or the other. From the view of the WoL why would we travel for months on a ship to go to Doma first when Ala Mhigo is right there in Eorzea? Also Eorzea is going to war with them so going to Doma first would mean that we leave them all behind from the very beginning. Also how would they do the story dungeons? I mean which level would it be, since it would be different depending on where you went first. Also why would Lyse go with us to Doma if she wants to free Ala Mhigo? No I think in the end this is one straight story line again. (I hope that this wont mean that we loose to Zenos twice >_>)