Blizzard should really think about dropping the glyph and giving Holy Nova to Holy and Disc back baseline. If they want to get rid of a spell to replace it with I'd elect mind sear.
I play disc and I never really liked it. Most times I was much better off just holyfiring and smithing and now penancing than mind searing. Not sure how it is for Holy but I suspect having Holy Nova back instead of mind sear would be better off for them too.