No, span loading is weight divided by span, related to aspect ratio which is what is what you are speaking of.
Yes, fineness is T/C and thrust loading is T/W
The performance under G loads is related to specific excess power, that is, wing loading causes loss of IAS, specific excess power is how the plane can overcome the increase in induced drag. The Thud didn't have a lot of Ps at high loadings or low speed.
I cannot speak for all transport category aircraft but mostl of them at reasonable altitudes can sustain 2.5 Gs for at least 180 degrees and need no more. At cruise levels, 1.2G or 1.3 G is about standard stall margins and sufficient.
Not many transport category planes have any need to exceed 2.5 G at any time and would absolutely need to only in an out of control dive recovery.
Wing loading is not a factor in any conceivable flight regime for the types of planes we are talking about. Transports don't engage in turning fights for survival or "scissor" with another plane to get landing priority.
Were it not for these "horrendously" high wing loadings they could not do their jobs as jet transports. Try designing a jet transport with a wing loading of, say, 50 lb/ sq ft.
GF