Hmm what can I think up this time..?
~ Updated Repel System - Definitely doing this.
~ Key Item Bag (to keep all Key Items with you, as opposed to using up so much inventory space) - I'm keeping the Gen 1 item system.
~ Bike Only areas - Already have plans for this because I'm not giving it to the player as an item. (The player has running shoes, anyway.)
~ VS Seeker or the ability to challenge trainers to additional battles later - I've never considered this. If the endgame requires lots of grinding, I'll definitely look into this!
~ Casino update, more rewards, possibly a new game or two? - I'm kind of leaning towards not having a casino... and having an arcade, instead! (Pong, Snake, etc.)
~ Quest Journal/Synopsis System - Meh. That's Fire Red's thing. I wasn't much of a fan.
~ Character Selection (2 for each gender or 3 for all male) - I would need to find some artists..
~ Gender Selection (^)
~ Hunger/Thirst System - No.
~ DNS - Already in the game.
~ Wild Pokémon by time of day - Yes, I've been procrastinating on this for a long time. Defining the wild pokemon on routes is my least favorite part of making this game.
~ .. I think that's it? - I guess so.
Just a few random ideas I threw in, to give you some ideas of your own, hopefully. The only suggestions here I'm really hoping for are Gender, Key Item Bag, VS Seeker, and the Repel Update.
EDIT: DNS is already in, right? xD