Dude. NO. STOP. Don't expect this to look like fricking GTA V all of a sudden.
Yes, the will change the way shadows are rendered, a bit of lighting, probably fix the models a LITTLE bit (like CJ wearing shorts.. his legs were so awfully done that I NEVER wore shorts because of that).
But DON'T HYPE IT UP SO MUCH. No, it wont be SA HD or anything like that. It will be just a normal, a little bit tweaked SA and nothing more than that. The mere fact that it's meant for smartphones and tablets means it will be played on smaller screens therefore the game will automatically look better as textures will be displayed in a smaller area and their poor resolution won't be as noticeable as on big screens. Same goes for polygon count on models. So just wait for it and judge it for what it is instead of hyping it up to be something it can never be and then crying here how it doesn't meet you expectations.