AIR INDIA had a few copies of those double bogie A320s. I believe intended use on rough/unimproved runway and taxiway surfaces and the relative load bearing capabilities necessitated the option, however as I remember it, a not so insignificant weight penalty applied as you alluded to.

New wings, a bit of a[737MAX9 to 737MAX10] stretch and possibly new gear, then you really have a 757 replacement and incidentally also the A321 NEO plus plus, which apparently is really a thing..on paper...