I second Establishment's argument. I'm currently at a terminal MA program, and most students here choose not to do a thesis. Not because a thesis is too hard, but rather because of the importance of taking a range of courses (particularly graduate seminars).
Graduate seminars provide much better opportunities for a concise, effective writing sample. Thesis papers are often done separately from the writing sample because they're too long and broad.
Our program has had great placement so far this year, and successful placements have been unaffected by who chose to do a thesis.