The ending fight was underwhelming compared to others but fitted well with the series as a whole. I think it's hard to compare ToQger other sentai series because it was a lot more subtle plot elements. It's surprised me that nobody else has mentioned that Right was dead the whole series.
For a little perspective for those that missed it........
Right died and peoples sorry from his death drew out the Shadow Line in the first place.
His friends "Imagination" brought Right back and also caught Zeds attention.
then towards the end Right remembers his death and his sorrow and anger give him his Darkness form.
Believing that because he's already dead he has no future he leaves his friends behind to fight Zed but loses because he can no longer imagine victory.
He's friends return and between their imagination and the town's wish's (imagination) to become break through the darkness and Right starts to "shine" again as he regains hope.
Zed absorbs his allies to boost his darkness to match Right's light but Right still has his friends and uses their power to become Rainbow and defeat's Zed.
Zed is saved by Grita because she know the light can only shine when there is darkness.
The rest of the ToQgers head home and because their family's still see them as kids they turn back
Right thinks he's still dead but then he's family see's him all their hope (imagination) brings him back for real
And ask for the end scene with kid and grown up ToQgers, because the kids can still remember and imagine their olders selves they can always become them again if they need to (ie VS Ninninger)
Between all that, Zeds creepy singing and conflicted personalty and everything Akira this series is a work of genius
Not really sure why you would think that Right was dead but that is clearly not the case.
The Shadow Line came about because they wanted to cover the world in darkness and with Emperor Zett nearing his full power, they were in a fairly good position to begin their plans to do so. Right was not dead at all, he was able to become an adult because of accidentally being influenced by Zett's darkness after trying to escape Subarugahama as kids, whereas the rest of the kids were influenced by the power of Imagination and the Rainbow Line.
The darkness Right had all came from being influenced by Zett's darkness and being exposed to even more darkness throughout the course of the series, just as Zett's fascination with the light came from accidentally being influenced by Right's shine at the beginning and the shine from the Star Festival lanterns.
The Toqgers were able to escape the darkness near the end mostly due to Right's mom making an extra lantern with a star on it for the Star Festival because she felt like she was missing someone. That lantern, combined with the rest of lanterns is what set off the chain reaction from the light that created the light tracks that saved them.
The parents were able to remember their children and help them turn back into children is mostly due to the letters that the Toqgers sent them during the New Years episode. That combined with the defeat and withdrawal of the Shadow Line and the freeing of Subarugahama helped increase the parents imagination also.
And lastly, Right over exerting himself trying to fight the Shadow Line all alone and then the destruction of the Castle Terminal and then Zett's final loss combined with all of the other positive events that happened is what helped Right break free of the darkness that was surrounding him.
There was no indication, whether it be subtle or not subtle that Right was dead at any point in the series, just forgotten because of the town being engulfed in darkness. The Conductor once said that they were "As good as dead." but that does not directly indicate anything, just that they were pretty much forgotten since their hometown was swallowed up by darkness and frozen in time by the Shadow Line.