With the thing about Seraphon being able to live on the Mortal Realms after being summoned by the Slann and even create cities we have room for new takes on the army, I Hope GW take it and make more lizards becouse I love dragons and lizards a lot (Ey GW, now that Dracothion helps the Slann why not an aztec-cosmic lizard dragon? I could buy 20 of them)
On the other hand, I know armies get emotional conection with the players since they paint them and all but I see the "lets make new minis that fit in our new setting" as a logical step, cosmic-magic dragon-lizards fit better than just aztec lizardman riding dinosaurs even when I love both ideas a lot. Of course you could do updates to existing armies with some new models and a battletome, but there are some armies that feel a little poor on the MR Setting (I mean, it's have been thousands of years after the End Times and the humans still fight like in the Old World times? not even a little of innovation having 8 worlds and a lot of years?) and it happens on all the GAs, not only Order.