As for speculation on what has been shown so far:
First we see the basic heal? Single target heal, possibly equivalent to Physick, Cure and Benefic. Short cast time. The swirl of magic on the Sage is white, first time we see this colour in this type of cast. WHM's and AST's are blue, while SCH's is green, alluding to the element they are using. The particle effects of the heal are similar to WHM's cure, possibly hinting at a link between Sage's magic and White magic.
Then the basic damage spell, equivalent to Broil, Glare and Malefic. The iridiscent halo at the sage's feet similar to Glare and Broil means this is an "unaspected" spell.
Here is the Shield spell, note that no casting animation is shown, possibly instant? Just like Aspected Benefic. We can't really tell if its an oGCD. Also note that the target of the spell, the Dark Knight is shown to have a white sparkly effect on him before the barrier forms around him. Maybe there is some form of combo spell? A buff you can apply that then heals the target once you apply the shields on them?
Finally, an apparent AoE spell. (It might be a single target strong spell too, given how certain spells seem to have big splash damage animations but turn out to be Single target, Blasting Zone or Broil II for example.) Note that there isn't any casting animation shown so it might also be an instant cast spell.
