I thought it was surprisingly progressive for Sun Vulcan to let female enemies be such strong and credible threats to the team. Most tokusatsu (and Japanese programming) of that vintage tended not to take female characters seriously at all or give them anything important to do.
I think Sun Vulcan using an all-male cast was a mistake, though. I seriously have a hard time telling the three leads apart, since characterization is not exactly one of Sun Vulcan's strong suits.
I thought it was surprisingly progressive for Sun Vulcan to let female enemies be such strong and credible threats to the team. Most tokusatsu (and Japanese programming) of that vintage tended not to take female characters seriously at all or give them anything important to do.
Not only it is the only sentai without an heroine, but almost all villains (Hedrian, Zero Girls, Amazon Killer) are female and human looking.
It could be called: good men versus evil women
At least, in Denziman, even if most villains were female, there was Denzipink.
You said they don't take their females seriously. That just leads me to believe you are new to sentai or you wouldn't have said something so for beyond reality.