I think that there is a failure to communicate around here. Technik's feat ONLY applies to Duration: Permanent spells. It's no improved permanency, since the spell is already permanent. The spell will never naturally end anyways, the feat simply makes it more difficult to artificially end the spell, and also gives a nonmagical means to end it. On account of this, I'd say it's spot on in all respects. I do agree with Seasong that it should be subject to large penalty instead of being outright impossible. I don't like Seasong's necromany spiel, but his clarifications are good.