fact is only the ones you mentioned are really any good so no need to ban them all. if they do ever make them actually good and worth their title of exotic then perhaps.
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Bungie wants balance in their game, which they stated doesn't mean everything does the same, but everybody is doing different things because one is as good as the other. Banning just a few exotics would be akin to admitting this one is superior to the other and they failed to balance them.