Most fights that require timed stuns to interrupt can be done by the very same PLD who MTs, granted they know the timings and the fight well enough, practice and you will see it is not that hard.
Only fight where there isn't a set in stone pattern would be chimera, and even then there is plenty of windows in between(besides you can't chain stun due to DR anyways) the abilites being cast.
Even easier if you OT, theres no excuse not to contribute to damage with combos in between interupts.