Summoner would not work with FFXIV current state.

[solracht]

It always kind of annoyed me that ancient and powerful beings were at the beck and call of everyday Joe Vanadiel, typically in the single player games somebody would have to do something to earn that kind of service.

If you really think so, then I don't think you paid enough attention to the SMN storyline in FFXI (and some of CoP) which is a shame. Personally I found XI had one of the best reasons in the series to give avatars to the players.

A lot of FFs are simply about the party defeating the avatar, and him/her being impressed and joining them. FFXI not only went a little deeper than that, but it also explained why it was good for a lot of random adventurers to be able to summon avatars.