Of course he was weaker than Queen prior to the powerup. That's the whole point of Oda giving him one. And I think it's a great powerup for him to get, because it addresses one of his major flaws that he's had throughout the series, in regards to his overall durability.
And the execution was perfectly fine as well. Oda had his body react to using the raid suit, rather than just going through this change all on it's own, for no explainable reason. There was a whole flashback dedicated to the potential of this powerup unlocking. It's not like it just came out of nowhere.