Following that assumption, is there any confirm from the devs about that possibility?

I really hope so. It feels pretty shitty to have to make an entirely new character of the same faction so you can just change color...

I vote Marines get to join Deathwatch temporarily

I reckon it would make sense to not be able to change the subfaction IF each subfaction had a formidable - fucking large, that is - selection of faction-specific customization options; a gazillion scrolls, artifacts and engravings for Bearers, all sorts of techno shit for Irons, Black Legion ponytails, stuff like that. Then it would be fair to lock a player in a subfaction. Until then...well yeah

But those sound like cosmetics, do i really want to restart another character just to get- purchase with $$$ for flashy bling and a new color?

I presume - only presume - that part of the reason of the lock is that we'll be getting subfaction-specific units later also. That, combined with - again - excessive exclusive cosmetic options would, in my opinion, justify the subfaction lock.

That is going to be a long, looonng wait for those subfaction-specific units.

No shit, my friend...its depressing really.

There's also the fact that we created our characters long before there was any difference between the subfactions, so it would be nice to be allowed at least one subfaction change when these things become a certainty (and if they're also more than cosmetic).