The most misleading thing about cmsplugin_filer_image is that the field caption renders as a title attribute, not as a figure caption.
I made a commit to change this behavior, but it uses the HTML5 tags figure and figcaption. Since cmsplugin-filer seems to be made for XHTML, I'm asking you if there's a proper way to do it in XHTML without divs.
I admit I don't have an opinion on that.
In a HTML4 / XHTML caption has no defined meaning, so it doesn't make much sense forcing any specific syntax in the default template which pretty much everyone would modify anyway.
I guess that post 0.9 release it would make much more sense migrating all the template to HTML5
Adding a center alignment would also be great.