-Main trainer will be customisable - standing in fromt of mirror at start, spriting glitch with accessory (when he swings across vine)
-Older Pokemon will be included from beginning and probably make up the majority of the new Pokedex - Pikachu intro, statue with a knight alongside Golurk, Palpitoad and Eevee when crossing bridge, Psyduck
-Final starter Evos will be:
In the trailer each starter does a STAB move followed by a move of presumably there other typing. The non-STAB moves appear to be Night Slash, Close Combat and Psychic. The dual-types also work in how each Pokemon will have a Super Effective STAB on the Pokemon they are traditionally weak against.
-There will be a theme of Genetics but nothing too excessive like Pokemon splicing - X and Y title names, ledgendaries, DNA symbol in Japenese titles.
-Grid based movement based on how the male character moves in the forest area. ie up down left right and no diagonal
-There won't be too many new Pokemon. 50-100 out of sheer numbers already - my opinion.
-No "bad guy" team. None in the trailer. I'm not sure if this happened in other Gens but it just seems a little odd.
Bear in mind most of what I've said come from different analogy videos from Youtube and not what I've made up.