well, I voted thats its too late to standardise. Look at the way some collectors now sell or moan and groan that the newer AFV's that have moved to 1/30th don't fit with the older 1/32nd stuff. If the manufacturers changed to smaller figures (for those that do larger figures under the elastic banner of 1/30th) then collectors would have two very distinct collections and, not many want that. The boat has sailed long ago for standardisation so, this is why we have in this hobby the playing around with scales to fix a problem the manufacturers caused.
I know lots of people who buy FOV AFV's and use K&C figures to accompany them. They don't mind the differentiation in the sizes as they are cheaper than the brands released in this hobby. It all depends on what you want from the available products. If your dio making then, it can be important, but, at the end of the day these are just dio's and, if you are going the full remit then having figures all the same height as is done is also innacurate so, you either grin and put up with the way it is or, find a better option.
For me, the scale of the AFV's is far more important and, in general the figures that occupy these are smaller than their dismounted counterparts. The figures will never change from what they are now for the companies who do the larger scaled figures.
Mitch