I think we all can agree- proper drag strips (Las Vegas in GT4 doesn't count), or don't even bother allowing for drag racing. I'm more of a road racing guy who doesn't mind watching some drag races. I think Gran Turismo, for bringing in rally racing and stock car racing, needs a proper and complete facility for drag racing. Nürburgring and Special Stage Route 7 aren't going to cut it. Proper drag racing on proper drag racing facilities will be a welcome addition for drag racing GT fans rather than set up these free runs on circuits.
The only exception would be if proper circuits with proper drag strips were included. There's only been one real-world track in GT history with a drag strip as part of it (if I'm not mistaken), and that's Infineon Raceway from GT4. Other cool additions would be if Heartland Park Topeka or Mantorp Park were featured. Both of which, having drag strips either adjacent to or part of the course.