Hey folks! So... a screencap of Ramuh turned up today, and one that was very interesting. Unlike most primals, who are often faced exclusively in combat or clearly tense situation, notice how, in the screencap of a cutscene featuring Ramuh that showed up today, no one looks like they're ready for a fight against Ramuh. They all look like they're talking to him.
I cannot think of a single moment in the entire Final Fantasy franchise where Ramuh is ever aggressive. At all. He is usually filling one of two slots:
-A defender. He always defends himself and the territory he inhabits when he plays defender. This is true in Final Fantasy V, where it takes the likes of Shiva and Ifrit to intervene and show Ramuh that Bartz and friends are not hostile invaders, as well as in Dimensions, where he challenges the party with full force, but then allies himself with them, seeing that they are, indeed, the Warriors of Light.
-A sage offering guidance. In almost every other appearance where Ramuh exists, he is always guiding the players, testing their wisdom and intellect rather than their strength in combat. In FFVI, he watches over Terra in Zozo while he guides her friends in ways to help her recover. In FFIX, he guides Garnet through a forest to piece together the story of Ipsen, to observe whether or not Garnet was worthy of an alliance with Ramuh, especially after her powers were used in the destruction of Cleyra against her will.
That being said, when I think of Ramuh in FFXIV, I don't see an aggressor like Ifrit or Garuda, or a combatant against invaders like Titan or Leviathan. I see Ramuh as being someone who only wishes to protect the Twelveswood and is willing to ally himself with anyone who shares his goals. In fact, when I see that Ramuh will be fought, I don't actually see that as "Ramuh must be defeated to preserve peace", because even if Ramuh fully manifested, I don't see Ramuh as someone who would immediately declare war on Gridania or the adventurers who have actually been trying to keep the Twelveswood safe.
I instead see Ramuh as fighting against the adventurers as a means of testing their skill and their resolve. If, however, there is an EX variant of Ramuh, I am willing to bet that the Ascians will attempt to forcibly control Ramuh, using their vast knowledge of the Primals to amplify his power and strip him of his free will.
tl;dr: Ramuh will not be an ordinary primal that you are ordered to dispatch, and will probably one of the most sensible opponents that the adventurers have ever faced, and will have perfectly good and justifiable reasons for fighting the party, be it due to testing the party or being controlled by the Ascians.