I think it's a good choice especially for studios like BioWare because EA have had trouble with the Frostbite engine which BioWare tried to make their games with. When it comes to Maxis I don't think they have had any trouble with their engine as far as I know, apart from it being originally supposed to support online play.
Apart from that, the sims4 engine have worked pretty well and from what I understand it was based on Unreal? They did their prototyping with it, which hopefully means that Maxis will not have anything against making The Sims 5 in Unreal Engine.
The thing that I am worried about is mod support, but from what I understand The Sims4 uses a python client which is why it's so mod friendly, and I guess The Sims5 will probably also use a python client but be connected to the Unreal Engine? So hopefully that means that The Sims5 will also be mod friendly?
Other than that I am happy with EA moving on to Unreal Engine 5 because it seems that there are a lot of people that are good at working with it, it also seems to be very flexible and powerful so Maxis will be able to make a game that will allow us to create the worlds we want and the sims we want, and in an art style which people will like.
