It's been a while since common Frenzy cards were introduced, and I think it's kinda OP in its current state. Now Frenzy is pretty much like Beast, but less hand-dependent, less time-dependent and even less rarity-dependent.
You need 2 Frenzies and 1 turn to trigger a keyword, and 5 Beasts and 2 turns to trigger a token. You get the same 2 additional attack for a common, 5-7 for an uncommon and full power for a rare. So you can just spam-spam-spam Frenzies and this bonus will never end. It's cheap and super fast. I have 34/17 with Frenzy rush deck, something like 13-14 Assassin awards, and most of those 17 losses were to bigbiger who built pretty much the same deck; any other deck wasn't a big problem unless I was very unlucky with starting hand and draws.
I think that Frenzy should work only if you have another non-common Frenzy in hand. Common Frenzy cards in hand should not trigger a keyword. Or revert a nerf to Call of the wilds to bring Beast on par to Frenzy again.