100A isn't difficult ... it's just tedious, in the same way that 6BL is -- only all the lab reports are done on the computer, which is great until you realize that all your calculations have to be Excel'ed in as well. Granted, that class does teach you some mad Excel skillz -- everything I use in Excel now was stuff I learned back in 100A.
Hale's essentially gone for good. He was lecturing as part of a postdoctoral fellowship (combined research/teaching for the 2004-2005 and 2005-2006 school years), was hired as a lecturer for the 2006-2007 school year, applied (but didn't receive) lecturers' security of employment (which is basically tenure for lecturers, that's why hoeger and weizman aren't going anywhere), and now he's in industry. I was his TA for his first quarter teaching, as well as his first quarter teaching 100A -- he interacts really well with the students and makes an extra effort to show them the "whys" of what they're doing, so ordinarily-monotonous tasks can take on a new meaning. The chem department made a horrendous mistake when they didn't choose to keep him, he was an excellent teacher and was really able to bridge the generation gap between the students and some of the 'older' lecturers. He saw me carrying a skateboard one day and asked to try it out -- and attempted a kickflip right there in his office! Awesome guy.
Feng's not a bad teacher ... just ... dull and boring.