Picture this. Everyone running around summoning Primals everywhere. 7 people standing next to the Aetherite all with their own personal full sized (or Hyur sized) Garuda floating next to them. Running into a Hunt and you see a full party of summoners all use Ifrit at the same time and it is dead instantaneously.
Honestly, in an MMO setting you cant really do a traditional, massive effect impact summon like you could in the offline FFVII (knights of the round!) and have everyone able to do this. It would totally cheapen the experience.
Aside from that is the whole lore behind it that with each summon of the Primal, the planet is being drained of its life energy. It's the whole reason we are killing the Primals in the first place and trying to stop the beast tribes from summoning them.
I'm a huge FF fan and I understand what most of you want out a summoner job but what you are asking for I dont think will bring you the level of satisfaction you are hoping for. This is how the devs feel about the job as well (correct me if I'm wrong). I really wish we could get some more current information on the status of the system but I read where their vision for the job is to have a Global Summoning System attached to the FC's.
From what I can recall from memory (this is old info and I'm not sure if it's even still going to happen) is they intended to have a Global Summon System to go along with what we currently have. The Primals would be roaming the Open World, sorta like Behemoth and Odin right now, There would be particular zones they will be more likely to appear in and anyone could attack it. (you can actually see this in one of their trailers, there is a group of players fighting Ifrit in what looks like Thanalan).
Once a group (assuming they are all the same FC) kills it, they now have the "Primal crystal" in their possession. Over a "two week" time frame the FC builds up an affinity with the Primal similar to how the FC gains levels (FATE's, Leve's, etc) and once that bar is full, they can now summon the Primal, at full size and strength, to use their signature move, once.
When the primal is summoned (and this part i remember clearly from the article) The skies will darken and (ifrit) the sun will burn letting the whole server know that Ifrit has been summoned. After its use the Primal will once again roam the land awaiting on another FC to claim it.
There are details that I'm hazy on and the information I had on it is now so old and buried that I cannot find it. So, if anyone has more current information or anything on this can you please link it to me? I have yet to see anything new on it since the open Beta of 2.0. My hope is that, with hints on whats happening with 3.0, it will come with the first payed expansion. Yoshi-P had said (regarding end of 2.0 start of 3.0) the same kind of event that ended 1.0 will happen again at the end of 2.0, but it wont be a complete overhaul of the game like last time (no the world will not be destroyed again). More regarding the immensity of what happened to the story.
I hope that means it will be something like setting the primals free to roam the land and the crystals become broken or something. With any luck it will set the stage for the global summoning system. We already know that more Egi's are coming for the expansion (at least Leviathan, Ramauh, and Shiva) so at least we will have that.
TL;DR
Can a dev or someone please, please, please comment to say something to Yoshi-P himself about the Global Summoning system? Can we have some sort of official detail on it? At this point I would even be happy and content with Camate coming here and saying "We havent forgot about it, its still under development and we arent releasing details at this time." or "What the heck are you talking about?"