Eg, particular features, types of pokemon, stuff like open world, etc
I feel like they botched open world in Violet/Scarlet. What they really need is some kind of difficulty options, like level scaling. I’ve done some hacking and it’s honestly really easy to make a toggle so that enemies are scaled to near your party and bosses slightly higher, or not at all if ‘progressing’/grinding exp is important to you.
Some interactions with wild pokemon that aren’t just murder, catch, or die to. Arceus experimented with this a bit in that you could feed them or accidentally wake them up, but I feel it could go further, like aiding one being attacked by another pokemon.The obvious answer for me is performance: hopping from Zelda TotK into Violet is a shocking experience.
Besides that, I loved legends Arceus because it felt like they tried something new. An increase in difficulty is also warranted, but hey it’s still pokémon.
I really liked the focus on collecting in Arceus. It felt like there was finally a purpose to collecting them all. The extra battle difficulty (plus the threat of over leveled wild alphas) was actually quite nice, too. By comparison, Violet was another faceroll in difficulty, with the notably exception of high level raids (on which note its weird for raids to be so brutal when every other aspect of the game is so mild).