There is good stuff in there. Please keep it up!
Comments: (I'll probably have more to say as I read, absorb and understand the implications)
1) I noticed you used Dawn of War II as an example of being locked out of a game by SteamWorks.
Please consider that yes, I did buy this game, but only because I really wanted it. However, I normally avoid Steam and Games for Windows like the plague. Please do not consider using the same tactics with Impulse... it's a step in the wrong direction.
Right now if I pick up a game off a shelf and it says "Impulse" on it, it does not turn me off from considering buying the game.
2) Get more Indie developers with their cheap $20 games. Most of these games I have seen so far on Impulse have not been interesting so did not make me bite... but if you had something like http://www.positech.co.uk/gratuitousspacebattles/ you can bet your ass I would have bought it the first time I saw it. (and yes, I have not bought something directly from impulse yet) *edit: I see that it is there this week, but I heard about this game months ago, which is another point you brought up *
3) For VoIP in Impulse don't use a closed architecture. Please use something open like SIP for message control. Infact, with all the work you've done for demigod peering, using sip and making it work should be a breeze. This would also probably be a money making possibility, where you could lease team servers for Impulse much like Ventrillo.
Now, going back to SIP. You could possibly let people build their own clients / servers if they know what they are doing by going this route. Think of it as modding new features for the voice system, which you could then include officially once the community demands it. The great thing about SIP is it allows you to support custom extensions while still working with the basic features on other systems.