Only DS9 and Voyager have not been converted to HD, it would be rather stupid to have TOS, TNG and Enterprise and not do the other two.
I'm not sure we're going to end up with either series in HD now. Sales have continued to erode for the TNG sets and the Enterprise sales look to be abysmal, to be nice.
But then, CBS probably made a mistake by putting TNG and Enterprise Blu-ray's out at the same time. I don't know who could've predicted that?