Here's my hope slash take on possible gameplay:

Disclaimer: Pure speculation with a dash of wish list.

Red Mage will have a buff effect that is either called Chainspell or is initiated by an ability called Chainspell. It will essentially be a haste buff. Refreshing it and maintaining it will be done via positional changes abilities, and the different positions will have different purposes. An example of a typical rotation that I could see would be to cast normal ranged spells while chainspell is up, jump into melee to refresh chainspell, perform a melee attack that provides a burst ammunition stack, jump back out to ranged which provides another burst ammunition stack, and then use those burst stacks for high damage spell attacks. Rinse and repeat. There'd be cooldowns to provide additionl burst stacks or instantly gain chainspell effect, etc.. E.g. Sort of a combo of monk and sunmoner.