The more they can make it agile and have less weight the better it will be for them. Its up against some stiff competition so when you have that with a model like this, even just something like weight reduction can mean a lot. After that most things should fall into place.
The biggest issue for me right now is confirming if this new XS model is the XF successor that's being talked about because with how new the XF still is and how much life is still left in that name, it might be a reason for them to not go with a new name. Plus "XS" sounds like something that could either be small or sporty.