Honestly, I don't really know. I think it will be about the same. Maybe slightly more than Alola. I don't think we will have another 5th Gen untill 10th Gen if we ever get there.
My hopes is that we get another Johto/Sinnoh like generation where we get a good number of evolution and baby pokemon. I am almost certain that we will be getting an Eeveelution in 8th Gen, mainly because of how much focus Eevee received in Alola Games and it is possibly that Lillie will be catching an Eevee in the anime.
It is a new system and they have a hell of a lot more room with Switch games than they do with DS games so who knows?
I will go out and say 110. Since they aren't dividing different pokemon up like Lycanroc and Oricorio, which all should have been a different pokemon, we might get 100.
I mean technically, we did get 108 pokemon in Alola.