This thread is really interesting and while I've been reading it I've come up with a few things. Firstly, I don't believe the song-writers who make it commercially are writing for the masses. Many of the famous are hugely complex both lyrically and musically. I guess they have good marketing strategies or for some reason people just like them. A few examples apart from those mentioned would be Gina Villalobos (country rock) Heather Nova some of whose songs can easily be performed in a folkie style at a club if you're so inclined and even the work of Alanis Morrisette and Jewel have a certain amount of integrity.
About work-shops: I think having a work-shop about songs by others you like is a good idea but why not take it further and look at how songs written by others have influenced then something you've written yourself. This often happens. I once wrote a song where I lifted a line complete from a Judy Small song. Probably not pc or whatever but the line worked for me so I used it. Sometimes we take a tune from someone else, adapt it slightly, add lyrics and call it our own. The ethics of doing this could make for some interesting discussion at a work-shop.
Yours in song-writing,
m