What purpose does Udonna or Trini serve?
Not everyone returned in Gokaiger. Not everyone will return in Super Megaforce. Just do what SPD did for the Dino Thunder crossover for Tommy and have a sound-alike actor with the suit (Hell, even Gokaiger did it when AbareKiller, TimeFire, and DragonRanger approached Gai in his dream).

The only past Ranger that looks to be returning is Jason Smith (Casey the Red Jungle Fury Ranger). He's been in images on set with Ciara Hanna the Yellow Megaforce Ranger.

So far the single best picture coming out of this new season. Then I'll say that for any picture with Ciara innit :lol

Sorry to double post but.. Trini's actress is dead, Matrix. She isn't coming back anyway.

The point being that not every actor who played roles returned to reprise them in Gokaiger, most of the time it was one or two cast members.

I know that.

People were talking about Udonna and Trini's actresses being deceased as if that held any point.
I want to know why their actresses being deceased has any impact on the series, since no cameo in Gokaiger featured a full team returning.

Udonna died?! When the bloody Hell did that happen?!

It's like the Legend War but smaller and with helmets.

In 2010 after complications from a brain tumor.
http://powerrangers.wikia.com/wiki/Peta_Rutter
http://en.wikipedia.org/wiki/Peta_Rutter

Your post made me think how much cooler this season would be if they changed into old Rangers by switching Helmets. Like Headmasters.. but with Power Rangers.

.. That sucks so much. I loved her as Udonna.