what lfs really attracts us is the physics, i.e "the real feeling"
so the next improvment of lfs should be mainly on physics.
NKP has show a great way on both physics and the feedback, but i'd say lfs has a great tire physics already, it's very different to any other sim-racing games, pretty special, if the developers could fix it better, especially on the slick of formulas, lfs would be the out-standing sim.
anyway, the most realear is the real racing, both nkp and lfs give me a lot of fun and different experience of racing. is great!