I'll probably push its mana cost to 7 for mimic's dagger. I was tinkering with its cost for a bit and didn't think it was playable on 7.
Gorehowl is better if you have the life to play it. I actually stole a gorehole from warrior on turn 3 with thought steal and found I was unable to play the card in fear of cthun or gromish. This notion is even more true against aggressive decks such as midrange hunter and ect. This weapon is more appropriate for priest since they lack the ability to stack up on life.
Thunderaan the Windseeker
Though, you can pre-equip the weapon on previous turn(s). E.g stormforged axe on turn 2 -> massive tempo swing on turn 4. You can also combo this card with rockbitter weapon. Wait until turn 5 and then, 6 damage tempo swing. It also combos with spirit claws, so you can use all the weapon charges on a turn where you have spell damage.
The card isn't for aggro shaman. It's orientated towards a control shaman.