Though, I think it's a damned if you do, damned if you don't here. People are upset Viggo isn't returning and will be annoying about the recast; but if he did and looked absolutely WHACK, then you'd have fans pissed and annoying about that too.
Personally, I have major respect for Viggo's decision not to return. I find the de-aging tech weird, & it is okay to allow others a chance. It's a call that each actor must make for themselves. I'm wary about this movie in general but wishful that ppl can give Dornan a chance.