I have mixed feelings on it.
The Good:
>Great soundtrack. Fixed a lot of issues I had with R/S.
>Fixed several story segments and felt a lot stronger for it. (Example: Fixed Aqua/Magma and made them more unique. Fixed your Rival and Wally and made them have more impact. Added little backstory segments like in New Mauville that were great).
>The soaring feature is something I really hope comes back or signals that they are looking at making HM's obsolete.
>Hidden Bases were greatly improved and were actually viable now because of QR codes.
>Delta Episode was great and offered a side of Pokemon we do not see too often.
The Bad:
>Used R/S as a template and not Emerald. Thing is, R/S were pretty badly designed and Emerald had several fixes that helped quite a bit. I really, REALLY wish at the very least they kept the gym leader teams from Emerald, or offered a hard mode like BW2 with those teams.
>Actually took out some content from R/S/E. Some stuff like the Trendy phrase were not missed, but stuff like the Game Corner (Could have easily been replaced with Mini-games), More widespread use of Pokeblocks, Safari Zone being gutted and made a normal route, and just a lot of little things from Emerald not put in. The new stuff honestly does not make up for it.
>Battle Frontier. Jesus fuck, why? I can somewhat accept it not being in, but using the Battle Maison from X/Y as a stand in felt like a lazy cop out and was clear they did it because a lack of time. THAT is what pisses me off. They could have easily made something unique and interesting for ORAS.
>Did not fix any of the slowdown or battle issues X/Y had, nor did they make any attempt to fix some of the shit from X/Y that needed some tweaks (Super Training, GTS, or online battling) were all copy/paste. Felt like a romhack of X/Y at times.
>General lack of endgame content. It had slightly more then X/Y with the legendary Pokemon and elite four refights, but that was it.
ORAS was a disappointment, sadly