I won't rule out there still being residual magic left within the Inquisitor. We don't know how the Anchor may have changed the Inquisitor either. But I don't think the Anchor is a danger to the Inquisitor now. But who knows, maybe the writers will decide they want that to crop up later.
At this point I'd just like them to announce whether or not they'll be making a next game since Weekes is being coy and always saying "should we make another game" and stuff like that. I mean, I know he can't just up and tell everyone that there will be a next game without permission. I just wish they'd officially announce it so we can stop with the ifs.
Well, the Anchor wasn't a danger for Inquisitor through most of DAI - eventually however the Mark began acting up, and we do know that its exposure to ancient elfy magic only made it worse. And given a 100% certainty that they're likely going to be in contact with more ancient elfy magic in the future there's no way to predict now what exactly may eventually try and claim their life.
As for DA4 - I'm afraid that even if they announce it, we'd still have to wait for the details for a while, especially if they were to announce early that they're working on the game... I mean, I think they most likely do, but if I'm not mistaken, I think they're now preparing the demo for EA, so the game wasn't given a green light yet.
Besides, even if they were working on the game and managed to secure the funds and everything was in their favor there's no telling whatsoever whether they'd manage to make DA4 the way they planned to - though I assume that plans for DA4 are much more concrete than plans for DAI.
We know that the game was supposed to be different (in fact, it was supposed to be twice a s long... only they didn't cut that part of the game as much as they've saved it for another installment, judging from Gaider's comments) and went through many iterations, only to be given another year of development, thanks to which we have additional races and romances, including one with Solas. I suppose they could at least tell us if, say, Inky is going to return in any larger capacity - I personally think it is inevitable, but HOW they're going to do that is another thing entirely. Will Inquisitor return as a portagonist? As a secondary protagonist? As a strange mix-up of NPC and controllable PC at some points? Just as NPC? As proxies and notes and war table missions or something? Uh, really hard to tell what they're planning and if they can pull that of.
As for me, I'm carefully optimistic - the old-gen is no longer hampering them (plus, I assume developing on 3 platforms rather than 5 less costly); they have Frostbite engine mostly figured out, with new modules created and polished and tested further with MEA; they have all the assets created for DAI that can now be further expanded upon, rather than created from scratch or refurbished from older games; they have a working combat/crafting/inventory/potion/leveling system; many of the lose ends from older games are cut or tied and they appear to have a pretty firm grasp on what they want to do in the future.
So as much as I'm pulling my hair out because I want DA4 *right now!!!*, I'm pretty confident that whatever we're going to get it and whenever we're going to get it, it will likely be something that I'll probably find satisfying 