It can, if there is a creature that has "wish" or "teleport" as an extraordinary ability (Ex) rather than spell-like (Sp)(link). Wish is rare enough that no creature ever proposed has had it as anything other than a Sp, but the Umbral Blot can teleport as an Ex.
In theory, Ex are better than Sp (they can't be counter-spelled, for example), but for the protean, it is a serious limitation when compared to unbridled shapechange, since the selection range is much more limited than if it could simply shape change into anything at all and gain not just their Ex, but their Sps as well.
Which in a weird way, it turns out to be an pro for the Protean-MitD, since we know Rich doesn't like unbridled shape change, but he might be fine with the limited (while still very powerful) ability of the protean.
Grey Wolf