I've tried this again with Custom movement... which unfortunately I cannot see the point of. Deceleration would be a nice feature...
I've also tried 8 direction movement, which is slightly more useful, but not great.
Physics gives me an absolutely brilliant result, apart from the rotation! The best result I can have with rotation so far is having the object disable manual rotation upon impact with something, but this isn't exactly what I'm aiming for.
If I were to be using a keyboard for the rotation, it would be fine, but I'm trying to use the mouse for a more accurate aim.
Is there anyone out there that can think of a clever way to combine responsive rotation with physics?