It's pretty good of course in dragon decks, but seeing how it's rotating out, I understand your not wanting to get them.
I'd recommend possibly book wyrms, drakonid crusher (forget how this is attained in relation to blackwing corruptor, so probably not an option either), dragonfire potion. Another potion of madness is pretty great too. It will almost always kill a creature, if not 2. Very powerful against aggro decks.
Dragonfire potion is only 1 more mana then holy nova, and does a lot more work, but you would want to ensure you don't run too many late game non-dragon cards that would get toasted too.
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