So I have come up with the following solution. Yes this would mean that summon would be getting a few extra spells but really what we have now is only about half way to what the summoner should be in this game. Not to mention summoner currently has 2 incomplete system that we use to play our class, would be nice to have at least 1 complete system to play with. Anyway back to my suggestion.
For arcanist Replace Summon 1, Summon 2, and Summon 3 with the following:
Wind Summon: Wind Spirit
Earth Summon: Earth Spirit
Fire Summon: Fire Spirit
Water Summon: Water Spirit
Thunder Summon: Lightning Spirit
Ice Summon: Ice Spirit
Light/Law Summon: Light Spirit
Dark/Chaos Summon: Dark Spirit
When the Summon job crystal is used they become the following:
Wind Summon: Choice of summoning Sapphire Carbuncle, Garuda, Bismark, etc
Earth Summon: Choice of summoning Topaz Carbuncle, Titan, etc
Fire Summon: Choice of summoning Ruby Carbuncle, Ifrit, Ravana, Belias, Enkindu, etc
Water Summon: Choice of summoning Aquamarine Carbuncle, Leviathan, Valefor, etc
Thunder Summon: Choice of summoning Amethyst Carbuncle, Ramuh, etc
Ice Summon: Choice of summoning Turquoise Carbuncle, Shiva, etc
Light/Law Summon: Choice of summoning Radiant Carbuncle, Phoenix, Alexander, King Thordan, etc
Dark/Chaos Summon: Choice of summoning Ebony Carbuncle, Diablos, Odin, Bahamut, Zodiarc, etc
For Scholar the following(WIP):
Wind Summon: Eos, Siren
Earth Summon: Selene
Fire Summon: Nyph
Water Summon:
Thunder Summon:
Ice Summon:
Light/Law Summon:
Dark/Chaos Summon: Imp
These would take up each a single action bar slot and when left clicked would summon the selected spirit, egi, or fairy, when right clicked it would open a roll out menu that would allow you to select which summon to to have access too.
This would essentially have the same effect as just changing the skin for the egi with the exception that it would not require the player to have to apply some sort of glamour item to change the appearance of the egi.
The final modification of this would tie in the new trance system for summoner. This change would link the attack ability to what ever primal egi is being used at the time. As an addition all the current summoner attack spells are non-elemental while in trance for a specific primal like Ifrit all the spells that don't have an elemental attribute would pick up that primal's attribute in the case of Ifrit fire. Which would lore wise explain the 10% increase in damage gained while in trance.
Update 10/27/15: Someone mentioned that with the increase in the number of summon spells people using a game-pad would not have enough action bar space. As it stands implementing my suggestion as it would only add 5 more spells to the action bar and as far as i can tell this would not cause any issues unless you have your cross bars full of macros for controlling your egi's actions directly. I may be wrong so if someone that plays on the PS would see if they would have room and let me know that would be great.