The leaker who has consistently been nailing details about Sword and Shield said there are 92 new Pokemon I believe,
as well as new Galar forms of some existing Pokemon, and unique Dynamaxing forms for some Pokemon.
That is bigger than the last two gens, but not by a lot. This decision is really irritating in that case. I could only excuse it if they had a ton of new pokemon they were adding like gen 1 or 5.