Hello everyone.

Literally just started Liveman myself.

Building it up would definitely have given it more of an impact, that much I can agree on.

Although, I don't think the show had no ideas afterwards. More like, no idea how to use their ideas in a cohesive way.

Heya. I've not seen Liveman yet, personally but I've got plans to watch it once I'm done with Bioman.

#1 fave thus far is Bioman for me.

Right now I rank the 80s series as this (only counting the ones I have seen subbed):

Dynaman (although I've only watched up to 30, so it could change)
Changeman
Liveman
Maskman
Bioman

Now if I were to include the ones I have watched raw Turboranger would be a the bottom of the barrel with Fiveman above Maskman.

Going by what I've seen of 80s Super Sentai, including stuff I've not finished yet, I think my ranking goes a little like this:

Changeman.
Dynaman.
Bioman.
Sun Vulcan.
Goggle V.

has Goggle V been subbed?

Yes.

Maybe it's a bit late but from what I've heard, Mika's actress simply disappeared from set and since then from the public eye in general. So no one could have found out why she quit Bioman in the first place and I guess the production crew couldn't locate her either to film possible out of suit death scenes.
I mean in Sun Vulcan they actually showed how the first VulEagle passed his powers to his successor, as they were actually able to make him stick around for a proper farewell before he went on.

Disappeared as in just went missing or just stopped showing up for the show?

I was always told that she didn't like her role (which was shown in her attitude when playing the character) and quit.

Disappeared as in dropped off the face of the earth after her role in this show.