Speaking of the more negative elements of the discussion, one complaint I have seen repeated on so many sites online is people saying GW will deliberately change the models available it so that it is impossible for people to use their past collections, I doubt that heavily as GW is clearly basing this heavily on nostalgia so what would be the point of bringing back the Old World but changing all the armies.
I can't believe that for example Dwarfs are back but the basic infantry won't be able to have shields, hand axes, handguns, crossbows, great axes etc
It makes much more sense that the selling point will be updated sculpts, new units to add to those classic armies and those updated sculpts for example Dwarf Warriors now coming with a new bonus weaponry option on top of the classic ways of arming them.
That is how they have handled Blood Bowl which is has been my favourite GW game for the last seven years before GW started supporting it again, they have added player options to some teams, rather then change them so that people would struggle to use their old team miniatures.
Hopefully they bring back most of the plastic kits that have vanished from AoS as with the new factory they should be able to manage it, as most of them are still great plastic kits even in the modern era, the one thing they need to avoid is not to do something silly that in my opinion would kill it on launch like only having rules for example Empire vs Chaos, then adding rules for another couple of armies a few months down the line.
Support all the armies from the start, even if for most of them it does not include any new models.