If you do Zilart missions, you can fight the original version of the AA fights. CoP and Aht Urghan progression will get you Diablos, Odin, and Alexander (where they are tied to the story). You say you want to do a lot of things, but it sounds like you only want to do what is popular now. So you upgrade your AF, what then? What will be left for you to do? Go back and do stuff where you are twice the level of the intended enemies? If you stop and think, doing it that way does feel like it is such a chore. Go from A to B to C where there is no danger is just like marking off a checklist. But make it so where the outcome is in doubt and I think your outlook may change and you might feel like you are making some true character progression instead of thinking anything less than the top is a roadblock to enjoyment.