>>38467338If they actually had a decent amount of Pokemon in the dex they could give very minor information out on a consistent basis without spoiling the whole game, say every month from announcement to release you got some new Pokemon revealed, Sword & Shield were revealed in February so that means you'd have March, April, May, June, July, August, September, October & November to give small announcements with February and June perhaps being bigger than the rest.
This is why a big dex is important, we know the dexes often follow a standard trend of Pokemon included so each month could go as follows;
Feb - Starters Base Form
Mar - Regional Bird, Bug & Rodent
Apr - Version Exclusive Pair
May - Starters Second Form
Jun - Box Legendaries
Jul - Fossil Pokemon
Aug - Pikachu Clone & Gimmick Pokemon
Sep - Pseudo-Legendary/ies
Oct - Mythical Pokemon that's distributed on release with the game
Nov - Starters Final Forms
This only works however if the dex has at least 100 Pokemon in it since you're looking at about 33 Pokemon being revealed which would be too many for a dex of Kalos or Alola's size. You can have sprinklings of information alongside those Pokemon reveals, new moves and abilities are the obvious candidates for this but also characters like your rival/s, the Professor, the first Gym Leader, the villainous team would help give the lesser announcements some more meat on them. Also although SS is clearly no graphical beast some location sweeping shots of the early areas of the game (nothing beyond the first or second gym) would probably work as well.