It varies greatly depending on your elevation and latitude.
I was there (based in Robbinsville) in 2011 on a dual-sport ride during that same weekend. The goat paths at higher elevations were covered in leaves, and we encountered snow on the highest elevations on the Cherohala Skyway (and the higher unpaved roads). However, the pavement was just fine.
Further north (northern tip of the GSMNP, Maggie Valley) about half the leaves were gone. Further south, the trees were still turning -- lots of green and mixed colors.
All the paved roads were in excellent shape, and the idiot factor was way, way down.
You really shouldn't let a fear of leaves keep you away. It's a beautiful area any time of year, but we had a great time because the crowds of goobers had vanished. No problems with traction on paved roads.
Be ready for precip and a wide range of temperatures (we saw highs in the 80s at lower elevations and frosty mornings) and you'll have a blast.
I'm the goober on the left -- this was at the highest elevation off the Cherohala, on the way to Whigg Meadow. Snow, leaves, rocks dirt...
Note how the frost and foliage vary with elevation:
Very high up on the Cherohala.
Pavement is fine, though:
Believe it or not, this was taken just a few minutes earlier on the other side of a ridge and a bit lower. Mountain weather is a bit changeable:
Parson's Branch Road -- that little one-way dirt road that pops out halfway through the Dragon. Lots of leaves, but still pretty green in this area.
Further north -- a segment of the BRP near the park. Leftover frost on the shady bits outside the tunnel. Air temps warm and pleasant, no problems on the pavement:
Devil's Triangle -- some INSANE twisties over in TN. Worth the detour. Go on a weekend so the coal trucks don't squash you.