The world is much bigger somehow, because you ride on Latias or Latios and explore new areas, the gameplay has become easier (as it has been every new generation), which has my fun but not harmed. So you can much more on collecting and catching focus, even targeted searches for only one Pokémon are now possible. What I find very handy.
Poké-Ami and the Suptertraining from X / Y are also back again, as is the beautifully simple connect with people from everywhere via Internet.
I am still not quite through with the Alpha Saphir, but so far I think it's great and it can all fans warmly recommend. Omega Rubin is likely to be just as cool - usually the games are different indeed rather on the small stuff. ;-)