I chose to avoid mentioning Blade Jack and Faiz Accel because they weren't strong enough to possibly fool viewers into thinking it's their final form.
Haven't seen Agito to comment on Burning or Trinity, though.

Agito Burning is very much like Kachidoki Gaim in terms of power compared to it's final form, and they're both "standby" versions of their final forms (Shining is Burning exposed to direct sunlight, Kiwami is Kachidoki with the armor cast off).

How you describe Mitsuru Matsuoka's song?

Is he like Michael Jackson, Bono, Freddie Mercury, David Bowie, or Paul McCartney of Kamen Rider?

Select your answer

A. Michael Jackson
B. Bono of U2
C. Freddie Mercury or Queen
D. David Bowie
E. Paul McCartney of The Beatles

Would you like for Mitsuru Matsuoka singing Super Sentai Song? Yes or no?

I wish Eternal have his own catchphrase

Oh... oh, god no. None of this. Absolutely none of this.

What's wrong?

I'm confident enough to answer for Switch. Because, for once, we agree on something. I know Switch, I'm scared too.

Mitsuru doesn't sound like any of those singers you just listed. He does his own thing completely. Bowie's voice as that lovely depth, Bono's carries with it the sound of an ego so massive he thinks we want his album without asking first, McCartney's voice has this certain lilt to it as he sings that no one can match, Micheal's voice is to damn high to be confused for Mitsuru, and he does not sound like Freddy Mercury. I grew up listening to Queen because of my dad. And so far no one I've heard sounds like him.

What you've done is list five or so people with such distinct voices that when they start singing no one ever asks "Hey, who's that?"

And as for Eternal having a catchphrase? He wasn't that kind of character. Eternal was more Henshin and beat your ass. Not stand there, pose, and say something witty. It would've ruined the character.

They may not sound alike (like in not at all alike), but Matsuoka and Bowie sure have both a very unique taste in style xDDDD

You're comparing some random J-Pop guy to five of the most iconic singers in the history of pop music, all of whom had careers that spanned decades and produced a ton of great songs. And you're comparing that to the dude that sings Drive's theme song, which is possibly the single most forgettable Kamen Rider theme I've ever heard (not bad, just really, really not memorable).

That and everything Sentai said.

What? I've tried reading up on her to see what happened. Was there ever an explanation of her whereabouts during The Next? Like was she still with Takeshi? I just found it odd that she wasn't even mentioned(from what I remember when watching) in The Next.

Fang I always saw as a mid-season form, as they had to go out of their way to make sure Phillip was on scene to use it, and unlike the other riders you listed W didn't really get any new forms in-between, as he already had all six of his standard GAIA Memories from the start.