I wonder if they'll go with Spellblade as the job's name. That is the most recent name used for the Mystic Knight; it was in 2008's FF Tactics A2: Grimoire of the Rift.

A year before that, neither Mystic Knight or Runic Knight were in War of the Lions (there's no direct representation of the job, which involves dealing elemental damage with sword attacks), but Beowulf is a Templar whose abilities are called Spellblade.

Out of those names (Mystic Knight, Runic Knight, Spellblade, and Templar), I strongly prefer Runic Knight or Templar. Spellblade just has negative connotations with FFTA2's incredibly shallow job system for me. You know, the job system where BLM has a total of 9 spells.

Then there's another issue: what would Mystic Knight be doing in this game? RDM already has sword enchantment spells. Maybe Mystic Knight would turn its attacks into that element completely, rather than just added effect.