What I think arcanist/summoner will be

[Alkar]

In the text I only read that the summoners once summoned the primals. Not that they can still do it.
I'm sure that the main primals like Ifrit, Garuda and Titan are still for free companies and summoner get the "lesser primals" like Siren, Fenrir an Typhon.

It's a lost art just like White and Black Magic. The WHM and BLM lores aren't any different really and I don't see what's the point in telling us what we can't do in the official description on the main website.
If we were meant to get lesser summons they would've said so but they only mentioned the primals.
It's like Scholar and Dancer in XI. People used to do it =/= people can't do it anymore. If mages in the past could summon the primals what's so different now?

[Arcell]

It's a lost art just like White and Black Magic. The WHM and BLM lores aren't any different really and I don't see what's the point in telling us what we can't do in the official description on the main website.
If we were meant to get lesser summons they would've said so but they only mentioned the primals.
It's like Scholar and Dancer in XI. People used to do it =/= people can't do it anymore. If mages in the past could summon the primals what's so different now?

They've said before that Summoner will get to summon lesser spirits/Primals, not the big Primals. So far the official statements have all said that the big Primals (Ifrit, Garuda, etc...) will be Free Company summons that only one can own at any given time.

This leads me to believe that Summoner will have access to smaller Primals or spirits. Until an official statement comes out saying that Summoners can summon all the big Primals at will, I'd stick with the official statements that have said that they won't.