Is it just really bad itemization on SE's part again (like the Ifrit Weapons) or a very purposeful reason to make all of the Sipahi Gear and Sorcerer's gear Rare/Ex, but only ONE piece of the Sentinel set Rare/Ex?

I would have loved to put materia into the Sorcerer's set, just like tanks are loving putting materia into their Sentinel Sabatons ;\