Summoner would not work with FFXIV current state.

[Neptune]

If Summoner is even added, I'd hope there would be no perpetual cost. By taking away the cost, other things could be done to make it harder on summoners without being too harsh.

With no perpetual cost:
Cons-
1. Make summon 50% of the player's mana pool.
2. Once summoned, the cooldown should be 3 minutes.
3. Additional 3 minutes, making a total of 6 minutes, if avatar dies immediately after.

I know wishful thinking. I would like to keep a summon out all the time.

Summons have to be out permanently, and summoner has to be the most powerful damage dealing class in the game. It was stupid in FFXI how you would pull out this awesome avatar, to have it hit for like 7 DMG.