The idea of NiFe resisting change confuses me somewhat. What's the point of -Ni if not to facilitate change?
Change is appropriate and needed in some situations more than in others. For example, I've changed schools 3 times because each afforded me a better opportunity than I'd had before. In politics and religion, progress is necessary to adapt to a culture that is constantly in flux. Same goes for technology.
Interpersonal relationships require constant change and adjustment as well, but instead of being seen as works in progress, many see them as endeavors that either work or don't work. I think this mentality is destructive and near-sighted, and the reason why many relationships end when they could have been saved. Mend it, don't end it, is my philosophy (stolen from the slogan to preserve social security, haha).

I think "unwilling to commit" is one of the popular phrases people use to accuse those whose priorities differ from their own. I think it is not so much about whether or not people are willing to commit, but where their commitments are.
Yeah, you're right, we didn't adequately define our concept of "commitment". In this context, I refer to commitment as devoting oneself not only to the other person, but to the relationship, imperfections and all (excluding incompatibility and other destructive factors). I feel that a lot of people get into relationships when what they truly want is a tryst or a joyride. This irks me.

The idea of NiFe resisting change confuses me somewhat.
Back to this...
accepts change, but sometimes resists it. I form strong attachments to others that are sometimes difficult to break, despite my knowledge that I must do so. Hence the gung-ho-ness about commitment.