As a fan I want cars that are fast in corners, with high lateral accelerations, and can overtake easily. That has been difficult to achieve because the former usually hinders the latter (KERS and DRS were introduced for that and have been reasonably successful).

Finally, remember that (almost) by definition Formula 1 cars must be the quickest racing cars on the planet measured by lap time. The latest rules reduced the aero package and made Formula 1 closer to GP2 and Champ Car.

Montreal circuit, from the Wikipedia page:

Formula 1 2004 1:12.275 Formula 1 2014 1:14.393 Champ Car 2002 1:18.959