What I never got about Power Rangers is why they always waited till the end to Morph into that big bad-ass robot and just step on the villian and be done with it.
It's about honor as a martial artist -- you don't use any more force than you need to, don't escalate a combat until you're forced to. Maybe it ties in with the post-WWII Japanese mentality toward military force, that it must only be for self-defense and never for aggression. But it's also a fairly universal principle of the ethical use of force, that you don't initiate an escalation. As it was phrased in Babylon 5
, "Never start a fight, but always finish one."
I suppose one could also assume that a Megazord battle creates the risk of extensive property damage and is thus a last resort, although that became less evident in the Power Rangers
version after 9/11/01, when all the Sentai footage of buildings being destroyed in the Megazord battles got cut out. Or one could assume that it creates a serious power drain for the Rangers or the source of their technology and/or magic, and thus needs to be kept on reserve for when it's absolutely necessary.
Of course, in reality, it's about keeping to the formula of the show and making sure you don't resolve the crisis until the half-hour is nearly over.
The conceit that always bugged me in early Power Rangers
was that the only people who did
know their secret identities were the villains. In that case, what's the point of having secret identities? And why don't the villains just kill them in their sleep?