In essence, despite the clamour and the rage, the lack of a National Pokédex is not the problem. The real problem with Pokémon Sword and Shield lies much deeper, or rather where that depth ought to be. There is far more than a whiff of troubled development to these games, brought about by an astonishing lack of complexity, texture, and flavour in almost every place where you'd usually find it in every Pokémon game that's come before.
Dungeons, in every generation until now, are the very essence of Pokémon games. They're where you find the most trainers, the most items, the most puzzles and the most interesting, mysterious nuggets of lore. In Sword and Shield all of that is gone, and there is no replacement.