RDM design seems just fine. Currently writing a "simulator" of sorts to go through and pick optimal skill pairings based on current state. On initial rotation, assuming we burn the 2x mana skill, we take between 8-10 GCDs to get get into melee. Without the 2x mana skill, we take anywhere from 16-19 GCDs to build up to 80. Likely conclusions are:
  1. 2x Mana cooldown is moderate length (30s - 60s), we go Short rotation -> Long Rotation -> (Repeat)
  2. 2x Mana CD is very short (15s - 25s) any double every 40ish > 50ish >Repeat
  3. CD is long (1min+) and we have a separate mana-dump to build to that *isn't* the core Spellblade combo
  4. Moderate/Long 2x Mana CD (30s-60s+) and doing just the 1 -> 2 melee combo is a DPS increase instead of waiting for the full 80 (so goals become 40 > 55 > Repeat)
  5. Combination of some of the above

Seems fine to me. Our AOE rotation is likely Shatter Spam -> the melee that wants 30+mana -> Repeat, whichever resource runs dry first (MP or TP), spam the other. So each one is primarily a spellcasting rotation with melee flourishes. This makes fits with how RDM has been in every previous Final Fantasy.