Bladed Hedgehog is a huge threat on turn 2, especially in midrange decks because you tend to trade more, anyway unanswered pushes for a lot of damage and personally I really like 1/3 bodies on a 2 cost follower, you can't trade it directly because 2 drops are mostly 2/2s, so you have to use something else... like 2 cost spells that deal 3.
Part of the reason Bladed Hedgehog makes a good turn 2 play is because of the supporting cards that come down the following turn. Eg; if you're playing first, play BH turn 2, your opponent responds by playing something on their turn 2, you can play Cuhullin/Lancer, Lancer of the Tempest, Princess Juliet, or even Novice Trooper in unlimited, make a trade, and either attack or make a value trade with BH (for example, if your opponent had played Goblin turn 1). Likewise, BH can draw heat off other tempting targets- tough decisions, like presenting a 4/1 BH or a 2/3 Mars with the expectation they can only down one during the turn is good play. Of course BH will die a lot, it's a prime removal target and common sense to take out quickly- which is one less removal spell for other threats you can present or a potential tempo gain if you're trying to race your opponent with face sword. BH is going to -average- as a 2/3 for 2, which is amazing. Sometimes it'll be a 1/3 for 2, which is average, sometimes a 3 or 4/3 for 2. It gets there fairly, though, making the card just solidly good as a staple 2 drop in most sword decks.