Everyone has different opinions
Some people may find ORAS has better graphics, such as soaring and mirage spots.
Some may find it the same as X and Y
And some, like you, may find that X Y is the one with better graphics.
So, there isn't really answer. Everyone has a brain (I hope xD) and so everyone can have a different opinion on the graphics.
To be honest I wasn't sure if this was even a proper question, but if you're really interested to know what people think, ask around on chat.