You're right that a bunch of divs like this is non-semantic. Anyone who thinks otherwise is crazy.
As far as the classes goes though, I would recommend that you check out a style like OOCSS or SMACSS (which I prefer) and give it a shot on a project. I style almost everything with classes currently, and I've found it much easier to maintain and extend than the style that you're describing.
It's a personal choice obviously, but I think you should definitely give it a shot and see what you think.
I've been wanting to try out a number of pre-processors, but I haven't figured out a way to be able to edit it live (which REALLY speeds up development).
However, I'll definitely give SMACSS another (more thorough) look.
As far as the classes goes though, I would recommend that you check out a style like OOCSS or SMACSS (which I prefer) and give it a shot on a project. I style almost everything with classes currently, and I've found it much easier to maintain and extend than the style that you're describing.
It's a personal choice obviously, but I think you should definitely give it a shot and see what you think.