Connectivity is better in the remake, probably the best set of connectivity features in the series. I'd also argue Gen 4 or 5 have a nicer set of core battle mechanics, as it's after the physical special split giving more Pokemon more options, but before the rebalancing of Gen 6+ where Fairy is a bit too OP and the big button that does a big special thing (gimmicks if you're not Yawnfag, whatever Champions will call that sort of thing that will absolutely not include gems because Yawnfag is completely unhinged for exactly Yawnfag) causing weird balancing sometimes on a game to game basis. It's not like Gen 3's mechanics are unusable though, it's completely serviceable unlike Gen 1. The only game that remotely approaches the main gameplay loop variety is B2W2 and the map design doesn't remotely approach Hoenn's if you want a solid campaign in addition to being spoiled for choice. Maybe HGSS has better side stuff outside that main loop like minigames or other alternative gameplay concepts, on top of solid variety when just considering battling, but the former comes down to taste way more than anything else. This still easily puts Emerald in the top 3 Pokemon games so that's nothing to scoff at. I personally value what HGSS brings to the table the most, and B2W2 scratches certain itches I have better, but Emerald has a ton of stuff I wish they explored more so I can forgive things like the slightly shitty endgame map design or the war crime that is the Battle Palace.
