Well, I honestly find both Plath and Sexton brilliant and am a huge fan of both. So, maybe I'm out of touch. I find them very accessible and, though not always, quite affecting more than affected.
I had the odd circumstance as part of a graduate class to go through Plath's actual journals and found Hughes edited versions somewhat odd or at odds. Plath was a little neurotic, but her early journals mark her as a creative caring girl with a ton of hope. Her early works were also masterful in their attention to form and detail.
Later, after the madness and treatments set in, she was as much a wreck from treatment as she was from illness. Her poetry reflected this shadow that she lived under and it fell apart in ways I find hard to describe. But even in that there are flashes of brilliance and truth.
I've seen confessional poets berated here before and I think it is probably typical of the next generation of poets, like rebellious teenagers, to reject the previous generations work in favor of their own idiosyncrasies. Make no mistake, their work was brilliant, if marked with insanity. I've never subscribed to the belief that "artists" need to be nuts to be good. I've also never felt that "artists" were special in that only they can do what they do. They are people who follow talent that, in America at least, is rarely favored with being well paid or even respected.
So, while they may represent the "damaged artist" I think their work is much more than that. Sexton's Transformations and 45 Mercy Street are particular favorites. Plath's early work I find better than her later work, but it is all quality. Don't cheat yourself by dismissing all of this work by labeling it. You'll find a great variety within the narrow definition their work is given.