Right now I have to use the dictation window of Dragon for having all of the handy features like correcting and spelling. I know that the Mac version ist much better with Dragon than the 1.9 Windows version.
Will the final version of 3.0 receive full native Dragon support in Windows as well?
I hate to disillusion you about the Mac Scrivener version, but…
To the best of my knowledge, Literature & Latte have NEVER changed anything about Scrivener in order to work with Dragon–not on the Mac, and not on Windows. Nuance changed Dragon to be able to work with Scrivener 2.x on the Mac, but since Scrivener 3 it’s back to Dragon’s dictation window or put up with Dragon’s numerous failings when trying to dictate directly to Scrivener.
Sorry to be the bearer of bad news… 
Silverdragon is correct. Any special support or lack thereof for Dragon integration with Scrivener comes from the Dragon side.
As far as I know, this is true of other word processors as well.
Katherine