For those that have been asking for interruption, I had an idea in VisuStella CTB:
Create a state called "Charged" or "Casting" that lasts one turn. Apply it to actor as an effect on each charge skill. Have a handful of skills that will bump the enemy turn order one or more spots IF they are affected by "Charged" or "Casting". Such skills could give bonus damage or drain MP, and could disable the state after use to prevent multi-targeting if it would be an unwanted exploit.. The downside is that it's one size fits all, and it won't know if they are casting at the moment, only that they used a time casting skill that turn.