Would have been sick to have Palpatine hiding in the sith shrine deep below the temple instead of Exogol, right under the noses of the New Republic and The First Order. Imagine the surprise of the destroyers emerging from deep below the surface of the industrial regions of the capital. A true power play.
Judging from this concept art this may have been the case in an early draft.
https://mobile.twitter.com/CultureCrave/status/1218324295765512192/photo/1
shit! what could have been and was not
we are going to make an opening that is going to shake our hands!