While adding a third category is an improvement on the traditional sim/arcade classification, I don't think its the answer. To be able to put a game in the "sim" or (shall we say) "semi-sim" category you need to define the boundary between the two. GT5 for example has added cockpit view, its added damage, what more does it have to do to move into the sim category? What is it that makes a game a sim? I doubt you'd get general agreement on that.
For me a perfect sim is something which simulates reality, and a pure arcade game is something which doesn't simulate anything real, such as Mario Carts. I take a quite a broad view of what makes something a sim - its about simulating everything. I'm looking for the perfect simulation of the cars both in terms of physics, graphics and sound, the perfect simulation of the tracks including changing track conditions, and I'm also looking to simulate the racing rules, the weather, and as an offline player the simulation of the other racing drivers in the AI.
For others its all about the sophistication of the physics engine - it doesn't matter if the car isn't real or the track isn't real. For some its still the old concept - the harder it is to drive, the more of a sim it is. And at the other extreme you have those who feel if you have to use the brake, its a sim.
So I'm not sure it realy helps to categorise. They are all imperfect, all incomplete and all compromises.
