I pretty much agree with Zantetsuken, I get the same feeling from Yoshi-P's comments that he wants to keep the God style summons as God like power.

Part of the issue is game balance. If you make Ifrit a summon, do you weaken him so much plus have every summoner have a version that you now use ifrit when you need fire damage and he "sycks" for anything else? Thats hardly paying homage to FF's Major summons.

Do you make Ifrit a 1 time summon with a huge cooldown so its like Dragon fire dive, how many 15-30 min cool downs would the Summoner class/job want? Cause if you had 7-10 One time major summons the cooldown would be huge to keep folks from cycling through them and doing absurd damage.

As far as a Summoner class goes, beside my personal opinion in favor of Yoshi's idea, i think it gives them the freedom to do something original with the Summoner class mechanics since they won't have the spector of the Major summons hanging over their head. We as players probably have less immoveable expectations from an Ixion summon then an Ifrit summon.

Mini Spoiler Below:

Another part is we've been exposed to an Ifrit and Garuda and their current strength already. Lore wise we've seen multiple beastmen summon Ifrit. (and they worship him.) Even though Lore can be used to explain most anything in context of a world, there is something to be said for maintaining a measure of consistancy. Even if my Free company isn't interested, when i'm out running around and i see the sky on fire that will be pretty cool.

I prefer Ifrit to be big, bad and dealy, as opposed to leashed to my side, no matter the lore explaination.