What i look for in the game is:
1.able to choose the starters in either from the four regions:either kanto starters or either johto starters or hoeen starters or sinnoh starters. Well you cant "choose" them but you can either catch them or obtain them through a quest or receive them for completing a cirtain feat such as completing the pokédex.
2.more training grounds: grass, caves, sea.Not sure quite waht you mean there but if you mean bye types of routes like desert and swamp that we havent yet seen in an official pokemon game then yes, that is what i plan to do.
3.even more trainer battles, double battles Don't worry, there will be plenty of new types of battles and lots of more people to battle.
4.anytime rematch trainer battles Well mabey not anytime but you definantly will be able to regularly re-battle trainers, possibley even gym leaders.
5.even more realistic animated battles I also plan on something like this.
6.can find the all-time favorite pokemon e.g: pikachu and some from the 4 regions. Well actualy you can travel to most reigons, but a few of the favorites will be there possibly with long awaited evolved or baby forms!
7. all legendaries available for catch I am a bit "iffy" about this one because i dont want it to be biased but mabey after a very very long side quest with lots of depth to it you get a chance to battle and potentialy caputure a legendary.
8.more apperances from team rocket, magma, aqua.Well i am kinda sick of the traditional teams so i scrached them and have 3 and 3 evil men only apart from appearences of magma and aqua when you travel to honen and other teams when you travel to there own reigon.