Gen 3 doesn't need a remake like Gen 1 and 2 got because you can still transfer Pokemon from Gen 3 all the way to our current Gen 6. This was impossible with Gen 1 and 2 until the remakes came. Now we can get all the Pokemon.
So because a new pokemon player could go back and hunt down a Gameboy Advanced, then copies of RSE games, then beat them, then buy a ds, then buy and beat one of the GEN 4 games, then go through the tedious process of Palparking them over, then buy and beat black or white, then transfer them again (which I assume is an equally tedious process), then transfer them to the Pokemon Bank and finally bring them to the new game... RSE doesn't need a remake?
A secondary thing I would like to note. You can use the argument that we can't play Gen 3 on the most current system, 3DS/2DS. If that is the case we can't play and Gen 1 games either. If Gen 3 gets a remake, Gen 1 should get one as well. As of today we can play Gen 2 (remake), Gen 4, Gen 5, Gen 6. This leaves Gen 1 and 3 needing remakes.
Gen 1 got it's remake, though. It wasn't "recent", but it got a remake. It was fun, and enjoyable, and was enjoyed.
I feel as though many people value it because it's the first generation they played or really payed attention too.
People will always value nostalgic memories. That said, RSE wasn't the first game I played (Red, Blue, Yellow, Gold, Crystal, Fire Red, Emerald was the order of Pokemon games I played not counting spinoff titles), and I enjoyed it and think it needs a remake. It had weird pokemon, and is overall my second least favorite (least favorite being gen 4, which I still haven't gone through more than once), but it was good. And I'll be damned if I let anyone tell me the Kyogre vs Groudon scene was only awesome cause of nostalgia, that was epic, and I want to see it on the 3ds.
I haven't noticed an excessive number of references to any particular generation. They all have a good number of references, it seems to be about equal. I think people are just picking up on those they want to see while disregarding the others.
I'm pretty sure there were a few more Hoenn references than the other regions, if only slightly. I think the majority of things in the Art Museum that were referencing a past game were referencing Hoenn, and there was the person somewhere talking about knowing the boat dude with the wingul, and the saphire and Ruby anniversery thing, and the minerals in the caves. But that doesn't mean I ignored the fact that one of the E4 is from Sinnoh, or the random girl in that cafe' talking about how different this place is from Kanto, or the painting of Unova, or any of the others sprinkled throughout the game.