There's a huge number of problems with Pokemon Sword and Pokemon Shield:
1) Pokemon models reused from XY; only change is lack of compression (which was previously needed for 3DS), and shading. That means models are incredibly basic and not at all worthy of what the Switch can offer. 2) Pokemon animations are incredibly static, lifeless and basic - Tomb Raider on the original PlayStation had better animations. 3) Move animations are still incredibly basic and lifeless too; Tail Whip, for example, just flips the user around and shakes them about - no actual tail movements. Double Kick is still just basic hops instead of actual kicks, a la Battle Revolution. 4) NPC movement is incredibly stiff, static, and robotic. 5) Insane amounts of pop-in. 6) Overworld uses very low-quality assets for trees and the like. 7) Pokemon in the Wild Area aren't tied to any thematic area, just wander about, and generally look very artificial and lifeless. 8) Over 470 (~60%) of 809 older Pokemon completely removed. 9) A slew of moves removed. 10) Mega Evolution removed. 11) Dynamax isn't exciting or a worthwhile innovation, since it's a temporary scaling-up of regular models only able to be used to specific areas. 12) Pokemon model size scaling is way off; Pokemon are way too tiny compared to what they should be. For example, Tyranitar and Wailord should be huge; instead, they appear smaller than the Trainers. 13) Box Legendary battle has no music. 14) Game is incredibly linear, leading to a tedious journey lacking in any kind of enjoyment. 15) There's an insane amount of free heals and auto-heals present, EVEN DURING THE ELITE FOUR CHALLENGE. You know, the challenge where you traditionally had to go through five battles in a row, relying on whatever healing items and general strategies you had? 16) Permanent Exp. All effect ruins any kind of challenge, and there's no way to turn it off, unlike the 3DS games.
DO NOT BUY THESE GAMES. If you're looking for an enjoyable RPG on the Switch, look at Xenoblade Chronicles 2, Fire Emblem: Three Houses, or Octopath Traveller. If you're looking for good Pokemon games, get a New 3DS XL, Omega Ruby or Alpha Sapphire, and Ultra Sun or Ultra Moon - or better yet, buy Platinum, HeartGold or SoulSilver, Black or White, and Black 2 or White 2 for the Nintendo DS.