I read a brief review of Lucie Brock-Broido's Master Letters in which the reviewer comments that Broido is "not a workshop poet." I've heard professors make similar comments about other people's work, e.g. so-and-so's work isn't appropriate for workshops. What exactly does it mean for someone (not) to be a workshop poet? What does it mean for poetic work (not) to be appropriate for a workshop?
A "workshop poet" is part of a particular artistic community (sometimes called a "workshop") whose members, through their shared aesthetic and the creation in a context of continuous mutual feedback, all write about similar topics and in the same style or "tone".
There was an article by David Dooley in The Hudson Review (Vol. 43, No. 2, pp. 259-280) about "The Contemporary Workshop Aesthetic", in which the concept is expounded.