Mirrodin is back, and with it comes a myriad assortment of...well, Myr. There were a few cards that rewarded you for playing a bunch of Myr in the original Mirrodin block, most notably Myr Matrix, but none were nearly as powerful as today's preview card:
This reminds me the most of Merrow Reejery, which is undoubtedly one of the most powerful lords we have ever seen. They both cost 3 mana are a 2/2's that pump their tribe, and both of their second abilities have the capability of generating a fair amount of mana. I'm not saying this is as good as the Reej, since Merfolk are a much deeper tribe than Myr, but the initial stats on this guy aren't as bad as most lords. Presumably, most Myr have sweet tap abilities, and one would hope that they go beyond the simple mana ability the cycle of Metal Myrs have (Copper Myr, Silver Myr, etc). For example, if there is a cheap Myr that draws a card or does something equally useful (though honestly, what is as useful as drawing a card?), untapping it seems like good times.
Much like Knight Exemplar, I don't have extremely high hopes for Myr Galvanizer, and for the same reason (the tribe they benefit is just too small), but unlike Knight Exemplar, the Galvanizer has the capability to do something pretty broken. Once we see more of the set we will know more, but I expect a ton of Myr to live in Mirrodin (they should have called it Myroddin, am I right?), and if there are a few with aggressive casting costs and good abilities, perhaps this guy can galvanize them into action!