Glyph of Riptide is a glyph really only used for very situational fights, especially because it is the only instant heal that shammies have, and the glyph nerfs that initial instant heal by 90%. In 5.4, the glyph gets slightly buffed.
Removes the cooldown of Riptide, but reduces the initial direct healing by 75%.
Blizzard has also reduced the mana cost from 16% of base mana to 12% of base mana. For a level 90, this means it now costs 7200 mana per cast, as opposed to 9600.
While not an amazing change, it will help a bit for those situational fights where the glyph is used – which also makes me wonder if one of those situational fights will make an appearance in T16.