Not a bad idea. But we'd have to take it up with everybody else.

but medieval knights was a specific theme....
and it didn't win.

That's why I said take it up with everybody else.

Here are my ideas for the team

Core 5
Fire - Red
Water - Blue
Metal - Orange
Air - Pink
Lightning - Violet

Sixth Rangers
Wood - Green
Rock - Yellow
They combine to make the earth element and are twins/siblings

Extra Rangers
Light/Sun - White
Dark/Void - Black
They can only henshin at the same time; one cannot use their power without the other. Yin and Yang

Spirit - Silver

I have no ideas on gender or anything like that, but I am excited about this and hope to be able to help in some way.

I completely forgot about lightning and ice. I like the idea of groups though.

All these element suggestions at once are getting very confusing. Let's just do the core five for now. It seems like we all have fire for red and water for blue. What should the other three colors and elements be?

I'd love black. And would love to mix things up by having it be a gentle element, like plants or flowers.

I feel like I missed something important. Are there cliffnotes of this current situation? I may contribute.

my core team would have to be

Fire- Red
Water- Blue
Black- Earth
Yellow- Lightning
Green- Wind (Just to shake things up by ditching pink)

The green for wind can work. It worked for Kuuga Pegasus and Wizard Hurricane Style. Overall I like it a lot.