As pretty much everyone else has noted, this episode started out really strong. Far stronger than I was expecting with the preview last week, which if anything set this up to be another worthless filler episode. Instead the RPG aspects were hilariously well done, and they nailed everything from the music to the graphics (even the dang copyright notice is spot-on). So clearly I wasn't alone in feeling disappointed when they transformed. It has to happen, it's Sentai, but more RPGing and less MOTWing would have really put this episode over the top.
On a side note, I was tickled pink by how nonchalant the guidance councilor was about Nagi wanting to be a ninja. As absurd as it sounds, he took it completely seriously and had Nagi investigate it like a real career. It's a great example of letting the humor be subtle. Also, I got a good chuckle out of UFOmaru doing the wasshoi pose at the end.
I am however more confused than ever about the Finishing Shuriken now. Does Troll-Grandpa have it? What exactly is the full range of its abilities? I don't fully understand why we're seeing it now (other than the obvious fact that we're approaching the final stretch).
And something I’ve been wondering since the preview last week - did Yakumo really have to wear a dress in order to be a mage? I thought maybe it was just a wizard robe, but on closer look it really is a dress with a cape.
Oh man, you're right!
Costuming must have really been in a hurry on that one.