After playing thru GT5 partway, I realized there are quite a few features I like better in 5 than in 6...
-Rally: There is precious little rallying in GT6, despite the large number of rally cars. And in GT5, the rallying is awesome! Randomly generated courses, 5-stage rallies, multiple surfaces...I really forgot how much I missed all of this.
-Top Gear/TGTT: This s a staple track for me, and as a big TG fan, I miss not having it in GT6.
-Course maker: Yeah, yeah, I know we're supposed to get it "soon". But I already have it in the older game...
-Length and breadth of Career Mode: Some people may disagree, but I feel that the Career Mode is much longer and more involved than it is in GT6. The longer the career mode, the longer people will play the game.
-Used Car Dealership/Online Dealership: This was a huge part of GT games in the past, and it sucks to see it go. I love the random chance at buying a rare car, rather than having them all available at once if you have the cash...
Overall, with the exception of the physics and some graphics (and the menu, and the cheesy music), I enjoy GT5 as much or more than GT6. It would be a clear winner in my book if GT5 were still online and fully functional. Aren't the latest versions of games supposed to be improvements??