Cool monster. As I remember back in the March/April '98 issue of
G-FAN the bloke actually made second place in a ranking of Godzilla's top ten foes. With the Showa Mechagodzilla placing at Numero Uno. I always assumed some of the cyborg's vulnerbilities came from the fact that the Futrians were on a tight schedule with what they could outfit Ghidorah with, because time was passing on both ends of the timeline before Godzilla's rampage in the present really screwed up things in the future. Also maybe the fault lies with Emi, Mecha-King Ghidorah's human operator, in that she was trying to keep the Big-G to a confined space, to limit the damage the battle would inevitably cause. Thus making herself and the cyborg vulnerable to Godzilla, who has no restraint when fighting. The cyborg really got to show its destructive side in the last

of the Random House, Marc Cerasini novels published,
GODZILLA Vs. THE ROBOT MONSTERS. In which a mad dictator, Kulgan Khan, finds the remains of the King of Terror, and has scientists in his service, resurrect him in a cyborg that lives up to term,
Weapon of Mass Destruction. And top it off takes on Godzilla, Mechagodzilla(Heisei), and M.O.G.E.R.A. simultainiously. Not to mention the the cyborg's operator is a teenage girl, Yisui, who through a virtual helmet, and wired in via neural links, controls the monster. But everytime she connects to Ghidorah's mind, she looses a bit of her humanity in the process. Twisted in a cool way.
I was of the thought, when I read that Toho had briefly considered the follow up to
GVsKG was going to be
The Return of King Ghidorah. Featuring the another King of Terror more faithful to the original coming from space. The idea started brewing that in the interim between the two films the Japanese had recovered the remains of Mech-King Ghiorah, and got the sucker in working order. When the new/original deal shows up the J.S.D.F. sends the cyborg to take it down. Which would've been on for the books. Although a nightmare for the wire works crew,trying not to get the wires tangled up. If they decided to replace the center, mecha head with a new one while taking apart, and reverse engineering the old one. I'd love for them to replace it with this one.
http://www.tohokingdom.com/concept_art/gvskg/mkg_head2.htm