I beg to differ; the only thing R/S/E brought were natures, abilities, contests, a better bag, double battles, the HM Dive and the running shoes, as well as a bunch of junky Pokemon and a region map consisting of too much water.
Meanwhile, G/S/C brought:
- Apricorns & thus the concept of berries
- Day, night, and overall time system
- Pokemon Friendliness & Evolutions
- Held Items*
- Pokemon Eggs, and thus, breeding
- Pokemon Egg Moves
- Shiny Pokemon concept (originally making Pokemon stronger, shinies gave way to the EV concept)
- First female character, Kris
- Animated Pokemon sprites
- The first PokeApp - the PokeGear
- The ability to decorate your room (unique to G/S/C)
- The ability to store money like a bank with mom (unique to G/S/C and HGSS)
- Rebattles with trainers and thus the concept of the VS Seeker
- The Special Defense Stat
- Male and female Pokemon
- The ability to explore two regions (unique to G/S/C & HGSS)
- The Pokemon Types Steel & Dark
- The battle tower, and thus the battle frontier concept
- The weather system
- The roaming Pokemon concept (G/S/C, HGSS, and D/P/PL)
- The virus PokeRus (its stat-affecting ability gave way to the concept of EVs)
- The HMs Whirlpool, Waterfall, and Rock Smash
and more.
* The Light Ball from Pokemon Yellow on Pikachu and the Twisted Spoon from R/B/Y on Kadabra doesn't count; you couldn't physically see them without trading to G/S/C
This means that EVs, berries, shiny Pokemon, trainer rebattles, etc. are ideas from G/S/C or not fully expanded / explored upon in G/S/C and therefore "touched up" in Hoenn, but originating from the second generation.
Not to mention, G/S/C introduced the only rival worthy of being deemed a rival, next to Gary, who, being the original, is incomparible to begin with. The G/S/C rival is more of a contrast feel with a dark past.
Compared to G/S/C & HGSS, Hoenn added barely anything to the game. It did add some key things, like natures and abilities, but for both in-game, trading, breeding, and competitive battles, G/S/C added a lot more.
Let's see an example...
MOST competitive battlers use Choice Band / Life Orb. Where would you be if Generation II hadn't invented Held Items?
MOST competitive battlers strive for great IVs and certain Egg Moves; where would you be without Pokemon Eggs, Egg Moves, and female and male Pokemon introduced in Generation II (apart the Nidoran series)?
MOST competitive battlers use shinies and PokeRus to EV-train their Pokemon; where would you be if G/S/C hadn't invented shinies and PokeRus, and the birth place of the EV idea?
Exactly.
Also, had breeding not been invented, abilities and natures would have become more tedious to have and acquire, since you wouldn't be able to pass it down by the mum. Your Vaporeon / Umbreon with Wish? Think again.
