You do realize that you just contradicted yourself there because the most basic definition of safe is a move that gives + frames on block.
Also, you've got it wrong. Safe moves (+ frames on block) promote attacking (and offense in general) because they mean that there's less risk involved when you do attack.
Safe on block in games like SC, for instance, definitely mean that you're safe from being punished after your attack. I'm not sure if it means something completely different for other fighters, but that's what it means. Moves that give + frames on block would be considered a Guard Break I believe in DOA, even though that term is weird. Using a Guard Break to force your opponent on the defense would be considered a frame trap.
At least, that's how it works in the SC community. Is the terminology different? Because the stuff I was referring to is the same.
The game should have more safe moves in terms of moves that are -1, -2, -3 on block, I believe (allowing movement instead of just blocking), but not string enders. String enders should still be pretty unsafe, IMO, because that still, along with the hold system, promotes people NOT finishing their strings. VF is a game where most moves in the game by far majority are safe on block, but if you're only using a couple moves out of your strings, in DOA, you should definitely be allowed to move after playing footsies. If you're finishing your strings, or getting to the launchers of your strings, you should probably be unsafe.
Personally, I don't believe in completely safe launchers/safe combo starters. In my opinion, you should at least be jab punishable, assuming you don't finish your string. Of course, in DOA, that means you're throw punishable, but maybe the push back can be changed.