Unless your users are of the kind who re-distribute your work (or something containing/extending your work - mostly aka software developers) all the time, switching from MIT to GPL is going to be just about no hassle at all to them.
Yeah, it wouldn't affect most users, but some users will be in that group. Plus it may (stupidly) raise legal term alerts for a portion of users it won't affect. As I said, is an option but one with concerns/considerations as per my last comment.
