Tossing this one out there: Add a class of spells that cannot be cast consecutively, you have to cast a different spell before this user can collect Mana for another cast. Sort of a halfway point between a normal spell (which can be cast as soon as it is full, even if it got filled as a direct result of its own casting, aka. “looping”) and a “one-shot” spell (which each side can only cast once per battle, regardless of user). It’s also conceptually like a self-silence, except it’s an intrinsic part of the spell and not a separate effect.
I’m at a loss for what to call it, but every spell of this type would necessarily caution that “this spell cannot be cast twice in a row” in its spelltext. (It would of course also be available as a filter option.)
For the UI side, where One-shot spells have a (/) icon to indicate they’ve been spent, perhaps these types of spells could have a similar but different icon (maybe (…) ellipses, or ( || ) “paused”) to indicate that they cannot be cast again until a different spell is cast first.
I’m also at a loss for what kinds of pre-existing spells should perhaps be classed with this typing. For example, the “PVP meta” seems constantly dominated by infinite-looping teams which necessarily mandates Freeze as a counterplay (which itself is easily mitigated with Bless/Cleanse teams), but it would definitely be nice to have more options against these loops.
Naturally, if this is the only spell available to your team’s side then you can only cast it once (“nonconsecutive” applies across the team as a whole, not individual casters) but in practice this usually implies (a) you are already losing the battle anyway (e.g. 1v4 in remaining Troops), or (b) you have extremely bad team composition.