I'd like to see Mecha-G brought back. If Toho decides to revisit the Hesei Era, and create a new Mechagodzilla. I'd be keen on seeing either something resembling the Trendmasters Powered-Up version(http://www.tohokingdom.com/toys/powerup_mg_trendmasters.html
), in which the UN-Mechagodzilla's designers took into account their original lack of ability taking on a physical threat. And built something that could take a pounding. Another favorite, is the SMG-IInd
from the the Godzilla Generations Maximum Impact
Atari video game.
Which looks like the UNGCC Frankensteined various spare parts intended for Mecha-G, and not wanting to waste anything. They also attached Mecha-King Ghidorah's head and neck. Even if Godzilla, the meaner more belligerent one, was dead, there was still a chance the Junior, now an adult. Could turn bad like his "father". Or else another threat could show up that would need to be dealt with so. So they put the SMG-IInd together, to have something in reserve.