When I first heard this new, I am actually pretty happy because it might end the conflict between AOS players and T9A players around me forever. However, after one day of discussion, I think that things are more than just simply everyone happy. Here is my personal ideas.How it will come out will depend on how GW will support the new WFB, which is called TOW now.
If it is just a 30k-style(FW) thing, I think that it won't do harm to AOS.
If it is something not FW stuff and it is something that has the same or very familiar set of rules with AOS supporting all fractions in AOS, then at least for me, it doesn't matter a lot it will do harm to AOS or not, since even if everyone turns to TOW, I can just do that too. Although it is very weird to use SCE fighting in the old world if GW supporting this.
If it is something with different rule set but not a FW project, then there will be some trouble, and how it turns out depends on how many resource it get. The more resource it gets, the more harm it will do to AOS.
First, I don't agree that this will bring the old WFB player to play AOS. In some chat groups discussion just hours ago, I can still sense the hatred of some old WFB player(maybe?I am pretty sure they play T9A) comment likes "AOS is a mistake, maybe GW thinks that it is time to fix this mistake". Besides, for the old WFB player, if they are willing to play AOS, they already did, why wait till now that they can just go to play TOW?
Second, for new player with limited money, if TOW and AOS are sold in parallel with similar price. I don't see any advantage AOS have against TOW on attracting new player, many new player might just be attracted to play TOW rather than AOS. For example, TWW attract many new AOS players(at least this is the case around me). The reason is most likely that the old world is so attractive but it is gone so play the alternative, but once the old world is back, why bother to play the alternative? Even current player will probably turn to TOW, I heard such comments already. They say if TOW is not too awful, they will turn to play TOW.
Finally, the more dreadful possibility is that GW earns a lot from this TOW and decide to create a parallel timeline or more directly, revert End Time itself. Then, good bye AOS.😞