Playing through Ruby currently alongside my wife who's playing Emerald. The amount of differences that I don't remember are SHOCKING and Ruby/Sapphire are much better games
>emerald adds a bunch of forced double battles onto every route
>holds your hand and forces NPCs to give you HMs after certain story beats instead of letting the player explore and find them on their own
>Wallace is the champion over Steven ????
>contest halls in every town gone and replaced by shitty battle tents
>Fighting both teams involve lots of tedium and backtracking in the late game that just feels like padding
>Free lvl 70 raquaza before 8th gym (I don't use legendaries in my playthrough but I can't imagine anyone thinking this is better than getting a lvl 47 at this stage in the game)
>Trainers and NPCs constantly calling you on your pokenav

The only good thing about emerald is the post game, every other change was objectively worse