Now this crossed my head. Bwahahaha! Enough. Cough. Headache. At last the idea is free from my head and now it's time to write it...
Sentai villains that die usually meet a more tragic and deserving end compared to Power Rangers villains.
In Super Sentai, villains have their own theme song and in some, their own song numbers. Bandora's group was a musical gang of their own. Bandora even had her own catchy theme song "Song of the Witch Bandora".
In Power Rangers, most of the supernatural were changed into aliens in MMPR. It was only in Lightspeed Rescue when supernatural enemies were introduced in the Power Rangers universe.
If any Sentai villain is dressed too sexily (like Zonette and Shelinda), the U.S. doesn't port them over for censorship reasons.
Many Super Sentai villains were downright more evil (and scary) than Power Rangers villains, which may have inspired the dark nature of Lost Galaxy's Trakeena. In fact, we see how evil they are when MANY civilians die in just one sitting. If one saw Zyuranger, Bandora is WAY MEANER than Rita Repulsa!
Also some Super Sentai villains were ported to become simply"guest characters. Shaddam and Exhaus are among the few. Shaddam was just known to MMPR as Mondo the Magician (a monster of the week) and Exhaus was just known as Goldyle in Turbo while in the Japanese version, he was the MAIN VILLAIN.