1. Field effects
2. Story; specifically characters
3. The system of axing Pokemon to force you to try stuff out
4. General trainer difficulty
5. The region itself
All I can really suggest is replacing Cacturne with Gogoat, it'll be a better physical sweeper down the road.
(don't forget to put a '/' in the second tag for gourgeist)
These are so precious xD
according to the characters page all that's missing is Victoria, Kiki, Serra, Corey, my main man Arclight, Bennett, Heather, Sigmund, Zel, Sirius, Solaris, and Lin... Oh boy!