Wisconsin flips but not PA? 
I could see Wisconsin and Pennsylvania both flipping if Trump loses traction in the Rust Belt, and Georgia could continue to trend Dem and flip, but I don't really see a high possibility of Ron Johnson's seat going down while Toomey holds on. Pennsylvania has been looking more hostile to Republicans since 2016 than Wisconsin has, and I don't see Toomey making up that difference with his incumbency/campaigning skills.
Republicans came out of 2018 in PA far better than they came out of 2006. Both Rendell and Casey won by more than Wolf and Casey did in 2018, Republicans ended up down 11-8 with a GOP gerrymander, and they tied the delegation this time with a fair map. Republicans also held the State House of Representatives, which they lost in 2006 and both times were with Republican drawn maps.
There was also the understanding that Pat Toomey was more conservative than Santorum so there is no way he can possibly win, which since he is now a two term Senator I think the results speak for themselves.
PA is and will remain a closely divided state and we will have to see what happens in 2020 but after McCain lost it by 10%, Dems picked up the Erie based seat (then PA-03) and secured their majority in the House, few people gave Republicans a chance. The 2010 elections are a cautionary tale of predicting long term dominance in a closely divided swing state.
I'm not disagreeing with your main point that PA is a closely divided state that Republicans can win in still, but I think comparing the Dem gubernatorial and Senate margins to 2006 isn't exactly fair. The country was a lot less polarized in 2006. You had Democrats win statewide races in the south by double digits in TN, AL, GA, FL, AR, and Democratic governors reelected in landslides in places like AZ, KS, OK, WY and what have you. The kinds of landslides possible in 2006 aren't possibly anymore (except in deep blue states where voters love their Democratic governors who call themselves Republicans). Essentially, when you account for the difference in national polarization, I would say that the 2018 PA Democratic showings were about as impressive as the 2006 ones. In no other swing state did Democrats overperform as much as they did across the board in Pennsylvania.
