I'm actually quite fond of the Thomas/Roth era for precisely the nostalgia reasons that other posters have mentioned. My first exposure to the X-Men, in UK reprints in the 70s, were the rematch with Lucifer from X-Men 21 and the Cobalt Man story from X-Men 31. A few years later, but still before my first real exposure to the new X-Men, I read a lot of other issues from this period and the Arnold Drake run. Without exposure to better days, these issues really don't seem so bad.