My two cents:
Gen 8 has a lot of bad animations, with a handful that were clearly made with love and attention. Gen 8 games are bad for numerous reasons, and the animation problem is more a cherry on top than a serving of ice cream.
The limited animations of earlier gen games may be considered bad by today's standards, but at least GF had the consideration to not go for something over-elaborate and instead focused on simplicity. In the simplicity of Gen 1-5 animations, our minds are able to fill in the blanks, which is what makes them feel much more lively than the more lackluster animations we see on non-signature moves in gens 6-8.
Gen 8's animations fall apart because the game is trying to present itself as more realistic than earlier titles, and failing to do so. Pyro Ball, Sniper Shot, No Retreat, they got treated well, but many other moves didn't. At least in the 2D environments of old, you could've imagined Pyro Ball or Sniper Shot being that way. Tail Whip? No-one imagines a Tail Whip happening the way it does in SwSh, and that's why it gets called out like this
