Well, I maintain that the only "proper conclusion" to Ash's story is no conclusion. It just never ends for him, one chapter closes and he's immediately thrown into a new and in many ways worse one and it doesn't matter one bit if we ever see how he gets out of that new situation, cause that one would also end with him thrown into another and another and so on... For Ash, every journey's end is just the start of a new journey. He's simply cursed to do this forever. As a matter of fact, I sincerely think the last episode of the show already concluded everything it started as well as it could, the last scene on the last episode already feels like a perfect ending to me. I've said this before, but to put a more definitive conclusion to this story is what would actually feel wrong to me.
I agree that the Season 3 ending is very likely the best ending we'll ever get (even if it did properly continue). But I'd still love to see a proper live-action continuation exploring what they had planned with Season 4. It can still happen.
An animated series continuing from where Season 3 left off, using whatever story they had planned, is totally bogus. That's something to be done when it's an absolute certainty there is no possible way it would ever continue properly in live-action form. For example, like when Bruce Campbell is either dead or crippled.
As long as he's still moving, still in decent health, and still yappingly contradicting himself like good old Bruce does, then there's still a chance Starz will get bought out and/or get a change of ownership/management that would favor and push for Season 4 (live-action) with everybody coming back.
Even if there was no more chance of that live-action Season 4, I'd still cringe at the idea of an animated series picking up where it left off. It misses the appeal of the show/movies (Evil Dead).
It would be like the pornography industry suddenly going, 'Hey, we're no longer going to do live-action, we're going to do animated porn, but your favorite pornstars will still be voicing!' And it's like, you're missing the whole point of why we watch.
We watch (Evil Dead) for the actors, the practical effects, the real-feeling world where all this wackiness feels tangible. (And, yea, I know some people are into animated porn, just like some people would be more into an animated Evil Dead over live-action Evil Dead, but I think you understand what I'm saying).