Just a thought I had.

I just thought: Why are the starter pokemon always fire, water or grass types? (Bar Yellow)

Why can't we have a different type to choose?
Maybe like ice, steel and ground perhaps?
I know that they have to form a 'circle' of type effectiveness (which my example does) But fire, grass and water is too obvious.
Or maybe it could be something that isn't in a type 'circle' and are completely random. For example, poison, flying and dark? Giving your rival no obvious advantage at the beginning, but instead starting on a level playing field.

I just think that it would make for a much more refreshing game and that they should've introduced it in black and white.

Hmm, yea. I've thought about that too before. Its a good point.
They probably haven't changed it because its traditional. And most older Pokemon fans wouldn't want some traditions like this to change.
And starting with Fire-, Water-, and Grass-types form the classic and simple "Rock, Paper, Scissors" concept. Its an easier starting point for beginners.
But, yes, something different like that would be a nice change of pace. Along with other game changes.