AOS did start with "You-could-use-your-minis" (excepted if you are playing Bretonnian and Tomb Kings) slogan... to appease the raging droves of WFB fans. AOS should be understanded as a cheap rebirth of the Warhammer franchise: so new rules, new setting with old minis ... at least at the very beginning and for some ranges.
GW wants the old veterans to come back and intrigued Total War players to join ... so the Old World -even if based during the War of the Three Emperors so before the coming of Magnus the Great and the Great War against Chaos so technically speaking during the 2nd and 3rd editions of WFB. Veterans could re-use their old Hero to LateHammer armies , spending some very solid bucks on new models, and no problem with slotta bases: Square is back! New players -the main target of GW- will have to sell kidney or kids to build their armies.
Remember GW is not the International Red Cross, maybe they are going to hire the Perrys' (not sure about in fact) to update some of their old models, same for every other ranges... excepted for Kislev, 2 units (Ungols Archers and Winged Lancers) and 2 heroes (Ice Queen and Tzar on Bear) are clearly not enough to form an army. So a major redo should be GW main idea, like W30k, new models based on very old ones veterans were able to play during games.
Cathay -good old Cathay...- will be the main new faction: back to the day, we had some pretty units till the Far-East just disappeared in smoke, so long Nippon, Hind, Araby/Arabia and Lustria. So I am anxious to see that army. 100% new models... some players are already selling kids to work in PRC factories..
I've never played to Warhammer Total War.. I (really) need to do some researches. But my deux Can cents on a major redo, in slowmo -slowly but surely my Precious...