Vitamin C is kinda over powered here.

What about the other stands? like Goo Goo dolls, & Bad Company.

I mean they're powerful, but the user just needs to touch things with their hands, and they all turn to goo.

...

Wheel of Fortune. & Little Feet?

Ooh, nice car be a shame if it turned to goo.

Bad Company shoots, and the shrinking stands shrink before Miraschon does anything.

The Vitamin C page says it can only melt living organisms and Wheel of Fortune is a bound Stand

They can just touch them before they shoot or shrink, also why'd they target Miraschon specifically?

We can see that is melts stands, so it would melt it.