Charlotte is notoriously undulating and bumpy, which slowed down the speed and made for good racing. Humpy Wheeler cut down the surface of the track to smooth it out. AAs a result the surface was very rough, with fewer bumps and undulations. The tire Goodyear brought to the track was designed for 5 mph less speed and a smoother surface. Wheeler will resurface the track before they come around again.
NASCAR needs to revisit their aero package. The teams spend so much on tweaking the bodies to increase downforce. Then you get an aero push in dirty air, which makes for less passing. They may as well hire some F1 aerodynamicists.
The best racing is when there's essentially no downforce. They need to bring the front spoilers up about 8 inches, so that it will be all about adjusting the chasis for mechanical grip.
I read somewhere that NASCAR intends to introduce a car with reduced aero. The code name for the basic car is "the Brick". I think that they intend to introduce it either this year or next, but I'm not sure how this effort dovetails with that of the manufacturers...