While I'm not sure if I really completely buy into what V's positing, I also don't know if we can really apply what we know about how dreams work to what we know about how Dreams work. Much of the Dreamer mythos is uh...well...based on mythology... which doesn't necessarily give it a firm grounding in the science of dreams (which we don't even really understand all that well anyway.) Plus we don't really completely know what the extent of Zoe's powers are or how they work. The info we got about it in Dreamfall was a lot of "Well...she's not a Shifter..." and "Huh. Yup. You're weird kid." (I mean, in a lot of ways, the Kickstarter info and teaser trailer was more straightforward about it.)
I expect we'll get more information about the limitations and extent of Zoe's powers once she "wakes up" (whatever that actually means). I'm hesitant on how much I want to really speculate about how it works without much info (especially because it's so much fun watching you all do it. )
Can you travel to the real Arcadia from the dream Stark using a dream dreammachine? I suppose that depends upon the extent of the effect Zoë demonstrated when upping her dosage.
The key piece here, IMHO, is that based on what we've observed of Zoe Dreaming herself places, it wouldn't be a dream Dreamer. It would be a real Dreamer that a solid physical projection of herself would be interacting with. When she Dreams, she ends up in two places at once and she has the ability to interact with real objects and manipulate real things. She's not in "Dream Stark." When she interacted with Kian and April and everyone in Dreamfall she wasn't in "Dream Marcuria." A physical manifestation of her Dream self was in Real Marcuria.
Basically what I think I'm saying is that it's possible that even if she doesn't need a Dreamer to get to Arcadia, it may help jog her memory and/or boost her powers or help her do whatever mental gymnastics she has to do to remember how to Dream herself into Arcadia.
Or maybe we'll find out that Dreaming works differently than we've kinda-sorta been able to infer it does.
Again...still not sure I like the whole "still in a coma" angle, and if it is the case, I agree with V that I'd rather have it be established sooner rather than later.
Ugh...is it February yet? I want answers.