>>37495189Held Items were able to make certain Pokemon more useful or viable (Thick Club Marowak, Choice Scarf Gengar to outspeed Alakazam, Leftovers).
Abilities also helped certain Pokemon to be a bit better (Intimidate Arcanine or Gyarados, Sturdy Golem, Levitate Weezing, Poison Point Nidoqueen) and have something special to choose them instead of Pokemon with better stats or movepools.
The National Dex helped many Pokemon to be more viable thanks to their evolved forms (Magneton, Golbat, Scyther, 5 Eeveelutions) with better stats, typing, abilities, new moves, and even access to Mega Evolution.
Removing all of this turns the formula into "fastest Pokemon win" all over again. Plus, having Mega Evolution just gives an unfair advantage to already strong Pokemon (Alakazam, Gengar, Aerodactyl) while removing some things, making some Alolan Forms less impressive.
The way they worked with moves is also pretty stupid. They removed every special Fighting, Rock and Ground move, physical Physic move, every elemental priority move except Aqua Jet, removed Defog or Rapid Spin to get rid of Stealth Rock, removed Hidden Power and any possible way to heal status conditions for your team.
Outside of the battle mechanics, they also fucked up the game in every other aspect, starting from the catching mechanic with forced motion controllers and without wild battles. Removing Pokemon interaction with anything besides your starter, breeding, any battle facility, and even day and night system. They already had a postgame area with a small story arc with the Sevii Islands but removed it for no reason whatsoever, and the only real postgame is a bunch of tedious grinding for gimmicky battles. Trainer customization got even more limited than in previous games, and the artstyle is shit. They fucked up the whole story by making Red and Blue two average trainers, and even the game itself is broken because you can literally take the entire Elite 4 with a level 3 shitmon.