Whilst playing the game I noticed a lot of references to the original RS, both small and large, have you? Let's see what we found! For me:
+ The game's opening is RS' original, same sprites, background and text before it pulls away to show that it's being played on the character's PokeNav.
+ 11 years is refenced a lot, a nod to the RS's release date in the west of 2003.
+A NPC in the PokeCentre asked you if you're suprised by Mauville's size and is seemingly amused you would be, in RS Mauville was much, much smaller. It was a single road with a handful of houses, a gym and other buildings.
+In Mauville Hills there's a character who's telling you his repeating his line for when he gives Rock Smash to a trainer, a character in a house used to in Mauville used to give you Rock Smash.
+ an NPC in Verdanturf Town tells you that the town used to be known as the gateway for contests. in RS, whilst the first contest hall the player will come across is in Slateport, they could only compete in the Verdanturf Town hall because it was the only hall that would allow begginer ranks whilst other halls had different ranks praticed there.
+ A Pokeblock machine is in the halls and an NPC tells you how they used to blend berries in a group of four people 'years ago'.
+ In the Safari Zone you'll find information that the owner used to charge enterance fees but after no-one would come he lifted the fees and made it free, in RS you was charged for enterance.
+ In Sea Mauville you can find a device on one of the shelves that has two screens and looks like what you're using now. Somewhat breaking the fourth wall and refering to possibly the DS or Game and Watch.
Delta Epsiode:
Delta Episode seems to incoprate of a lot of Emerald elements, ones I've noticed:
+ Steven calls you up using an early version of PokeNav communication, Emerald's PokeNav doubled as a phone.
+ Wallace's team when he rebattles you is the team he uses as Emerald Champion.
+ RS' Hoenn is referenced as a place where the Pokemon War never took place and some evoultions weren't discovered, some Pokemon in RS would be given future evoultions or mega evoultions and in ORAS are considered Hoenn Pokemon now. (Dusclopes, Dusknoir etc.)
+ The Battle at the Mossdeep rocket station is similar to the battle with Team Magma in Emerald.