I think the confusion might be in that silence was previously a status that would prevent "silence-able" casts. But now, interrupt is an action that will immediately interrupt any interruptable cast that is in progress.

Unlike before, you cannot pre-silence to prevent casts, and interrupting things that were classically silencable, like the quick casts on sprites or older caster mobs, are much much harder to get the timing correctly on.

The system was translated, but not in a way that maintains the same gameplay feel of the early early levels.

Not that I think that's really a problem. I like the interrupt system, personally. And silences were never really consequential in those situations.