I think it looks good as it is. I use a flannel backed table cloth pinned to my wall. They are so inexpensive I have more than one, that way if I'm working on one project and decide to start another, (which I do) I just take the one down and roll it up till I'm ready to work on it again.
A hint I got from another site for a portable design board:
Foam core boards covered with flannel make a great portable design board. Also a lot cheaper.