how many commander's will their be total for each army when the game is release?
5 per faction for a total of 10 at launch.
That's per Greg Wilson five days ago, and it turns out it's complete bullshit. There's seven, apparently, and they just didn't mention that two per side were paid DLC. Really quite frustrating. I hate this model. That Commander that Inverse linked is a textbook example of why paid Commanders are a bad idea-- it's just rearranged abilities, but "all-star" commanders are really good.