Now, lets put your post against some facts and things we know.
Concerning that the friday announcement will probably be something big and Noun stated that the next commanders and ToW missions wont come too soon AND since we already know that Relic worked on different commanders (not including a lend-lease one) months ago which probably will be released first, what else should it be?
Relic stated there won't be new commanders and ToW THIS MONTH, this is all they have said, nothing more.
We don't know what commanders they were working on, we had a couple of leaks, but there were plenty of other commanders there as well, some with placeholder icons. What makes you believe there was on land lease commander amoungst them? Land lease project existed.
Americans on easten front not.
What do you think we can expect from the game that holds some historical basics?
Furthermore this kind of teasing, as we can see by having this debate, can be very misleading...and is not something I as a developer would do just to promote a future commander dlc. And I bet that the folks are Relic are smarter than me! 
Its called marketing. Building up huge hype for small things.
Remember mud tech? Much hype. So useful tech. Wow.
On the other hand there are no arguments against an american faction.
Except the historical argument backed up by facts that point out there was not a single american soldier on the eastern front?
Battle of the Bulge simply works: Not too much work (compared to the pacific with 2 new factions and they can reuse stuff from vCoH), ColdTech and the US army being quite popular.
D-day also could work and be easily implemented. That doesn't mean it will be in.
It can also be a lend lease commander (since we've seen what appeared to be one in an early video) but considering the facts above that seems odd to me.
Except if Kursk is known for lend-lease US weaponry, since that is going to be the "next ToW-step"...such a DLC would be big enough for this kind of announcement as well.
Land lease commander and Kursk(since they plan something bigger for it) make sense.
More then that is day dreaming really.
Game isn't even 1 year old, if we will see new armies, it will not be soon considering commanders give close to infinite expanding on current factions.