Double dilemma! Realism or fun? More details or simpler graphics?

As the title says. Double dilemma. What should I do? Make a game which is closer to realistic in term of physics or make it simpler but easier to play. Also what about the graphics? I tried out different approaches for making it nice and cartoonish, but which method is the best? Let's find it out!

Little progress... Tree and track design

I am getting on the right track with racing game development in Unity. I have a decent (but far from great) car physics for mobile, and now track design is getting better too. Also, I figured out, how should I make tree sprites quickly in high quality.

Crossed tree sprite in the background... well I won't leave it there it's too dangerous!

My first artwork with a tablet PC...

Finally, I bought a Nexus 7-2, and I am very happy with it. I don't have a pen for it, but I made one. It's pretty horrible. But it works. Here is my first artwork I made with it. I cheated on the outlines, I used a background layer to draw on the top of it.

My picture is related to the famous 1976 Formula 1 World Championship, which is recreated in the movie RUSH. I never made any digital art, like this, but I'm happy with the result.

Tablet: Asus Nexus 7 2013
Stylus: Homemade from old pen, Q-tip, aluminum foil
Software: Autodesk Sketchbook Pro

Also on DeviantArt: http://ratmanxx.deviantart.com/art/James-Hunt-Mclaren-M23-1976-405740641