You draw, find the Elemental and immediately play it on turn 5.
Oh my, your Druid opponent plays 2 Innervates and an Alexstrasza!
Your only hope in your hand is a Lightning Bolt with a Lava Burst. Alexstrasza is gone.
You have a 4/6 Unbound Elemental on Turn 6 and 3 mana available to use. (I'm not badmouthing Overload spells, just the minion.) Gee, that's just wonderful.
Maybe if it statted up for each overload (Lava Burst is 2). Or if each stat was 2/1. Also, I find it hard to believe that there is only 1 card that rewards you for playing Overload. Add more minions like this (better ones, preferably) and maybe a spell that draws cards for how many overloaded Mana Crystals you currently have. That could be a bit broken, but you get the idea. Shaman could use the buff anyway. What do you guys think of this?