The 1 mana spell wasn't the problem.
The problem was that the Gnoll was able to be cheated out early and be evolved into a small pool of 10 mana minions since there is no 11 mana minion currently in Standard. The low-rolls could be another Gnoll while the higher rolls would be a 12/12 Deathwing, 8/8 rush with windfury, and the most offending one being Thaddius who is basically mana cheat incarnate.
Besides shaman has other cheap evolve spells that do the same thing, Blazing Transmutation is just a spell that makes it a bit more consistent. They could've printed out an 11 mana giant minion which would cut down on the highrolls.
Anyway here's my salt for the day, screw you Curse Implocks who spam curses to win against anyone who managed to survive their onslaught of imps.