It is a choice, but a great many people have a preference for it. I have used Impulse only for Stardock games, and it is a pain to have to use another client. Just a few weeks ago I bought five copies of Trinity on Impulse as gifts for friends, not knowing this was in the pipes, and I've now got some serious remorse.

Is this decision final, or is it still a possibility that can be investigated?

Keys purchased from Impulse are tied to that service and we can't give them to Steam. It's more technical than anything.

On STEAM?  About time!  hehe 

Also I have a question about something. I will buy the game again from Steam I think but can I use my old Ironclad Account for multiplayer or I need to create a new account for multiplayer? I am asking this because Steam and Impulse serial numbers are different I think for multiplayer.

Well technical was a broad term.  As I said, current keys are tied to the Impulse service, so they won't be transferred.

Can I get answer for this question please? Thank you.

Trying to get a definite answer....standby....

I am very happy the game is available on Steam since I never liked Impulse. But I think you are missing a key feature, i.e.  making the game available for free -or very very cheap- to the people who already own the Impulse version.

This should be a priority.

Alienating existing customers is never a good strategy.

I'd already sent a mail to Stardock support to see if I could have this done (remove the Impulse license, give me the Steam one), but they told me it was not.

I imagine the GameStop guys would have quite a bit of reason to prevent that kind of thing from happening. That maybe the very problem they were talking about.

What I meant is that with Steam, people buying the game now have an overall better package compared to people who already have it on Impulse. The customers who bought and supported the game in the past might feel left out -alienated- of an important improvement. I know I do and I bet I'm not alone. 

Instead of re-purchasing, would it make sense just to wait and get Rebellion on Steam, which will have everything (it will right), if one were so inclined?   (Just a general question, I'm comfortable with my previous pre-order decisions.)

Lets remember the Stardock store is the preferred place to buy our games, obviously.  Steam is just another outlet we are making our games available on.  This does not affect your current game, and we aren't giving away keys just so they can be applied to another platform.

Sins: Rebellion pre-orders right now are Stardock store only, and will likely remain that way for some time.