I too had issues with most of the last tier of Expert Guitar.
RTtH was really a pain in the *** for me because the solo was tough, and the section right after the solo was even harder. Finally, last night, after practicing the solo for an hour, I was able to get through the solo without Overdrive, and was able to use the full bar of overdrive after the solo to get through the damn song.
Now I am trying to get through Flirtin w/ Disaster and GGaHT. GGaHT I can make it all the way to the G,R,Y,R,G,R,Y,R,G section in the second solo (80% through the song) and I lose it. I have started practicing doing a finger slide across those 3 buttons to get through it, but I am not quite there yet.
I won't even go into the hate I have with Flirtin. It was a pain on hard, and its twice as bad on expert.