I assume that people here know what pokemon is so I'll go on to whats new or different.
A new region consisting of 5 Major Islands and 5 Minor ones.
A new type, light.
A new professor, Professor Spruce.
107 new pokemon
50 new TMs/HMs
A bunch of new moves and abilities.
2 new evil teams Team Moon, and Team Sun.
New gyms, but how many...
New Elite 4, (not that that is that new but...)
A new contest system (maybe one thats more people would like...)
D/P battle system
493 current pokemon
A couple cameos...
The site I'm working at is here
Please come and look if your interested!