Well Pokemon could dang well use some actual choices like you would find in a proper RPG.... =P
In every game huh... that's kinda hard. Like there's certain mechanics I've seen in a certain game that I would like to see in other games of the same type... like Crash Bandicoot has this system where it creates additional checkpoints if you die too much. I found it very helpful and would not mind seeing that in more platformers at all.
For RPG's, well see above for an example =P
The thing with mechanics is that what works well in a certain type of game isn't necessarily going to work well in another type of game.
Idk.. a good, clear, not overly clunky UI maybe? There's definitely games that do that better than others.
What's your preferred way to spend a vacation?