But then people would be monumentally pissed because they would see that as GF actively deceiving them (because it would be). My problem with the dex controversy isn't just that a favorite may be left out, but it's the next symptom of a more and more noticeable string of problems that Pokemon has had over the generations. Gen 6 had an area that was completely locked off, but insinuated that something was up (the power plant on the desert route). People thought we'd see it in the third version. We got no third version, the national dex in that game largely reused descriptions of pokemon not in the regional dex, there was barely any post game, not to mention the whole ORAS battle frontier fiasco. They didn't even bother to copy/paste Pokemon not in the regional dex for all of Gen 7. Very little changes were made in S/M to US/UM compared to their Gen 5 counterparts and while there was a bigger after game, it still felt lacking.
Another problem in the "we're not including the national dex so we can work on more animations, etc." is that it's not holding any water. At all. Something Pokemon that hasn't been bashed too much over the years was their quality of animation and graphics in general because they've been able to uphold some sort of standard of fun for their audience. Now that they're moving to a console which has more of everything, fans are told, "Nah, fam, not enough space," which is completely untrue. If you can fit 800+ creatures on a hand held, you can fit them on a console. I digress, the animation and graphics in Sw/Sh aren't all that impressive in terms of normal games. In terms of Pokemon, heck yeah, it looks great, but we're used to seeing pixilated stuff on a 3DS screen.
Take a look at Hop's animation in the trailer. It's exactly the same as Hau's from Gen 7. They're just porting stuff. Look at the Pokemon's battle animations and compare it to Genius Sonority (the people who worked on the Shadow games and Battle Revolution). The Pokemon have unique animations. Kecleon is twitchy, Hariyama is constantly doing these sumo wrestler gestures, Monferno gets aggressive and roars before wiping his face. We already know GF is recycling all the animations from Gen 7. Scorbunny's idle animation is kinda fun, until you see the animation of the move double kick which it keeps the same animation and barely rises off the ground. My point is that Genius Sonority did it, so why can't GF?
So it's not just that "X Pokemon isn't in it, so I'm mad." It's the latest in a series of "mainstays" with Pokemon that have hit the wayside more and more with each generation. Things that built up over time that people noticed, but didn't really raise alarms about. I'd be happy for them to delay the game if it meant that paid more attention to it/did it justice. Oddly enough, I think Gen 5 was the last game that really, really had the effort put in to it and I don't even like Gen 5 as much as the other gens. But anyway, rant over.