1) Philosophy of Language sucks... really...
2) I think that writing/research is considered important because it is harder to do than teaching. It is hard to write a good paper, easy to teach a class --- or, at least easy to teach classes when you have a TA to do the grading, students with decent ACT scores and can actually read.
Even with my high teaching load (5/5 baby..) I still think it is easier to teach than to write.
Of course, #1 may explain that as well.