The starter post ( a long way up )talks about size then finishes on scale.
When I buy a toy car for my 4 year old grandson I ask him whether he wants a small one to go in his garage or a large one for his teddies to ride in and lots of different sizes in between. I would be wasting my time saying do you want a 1/76th, 1/43rd, 1/24th etc toy car.
I find it strange that size and scale are confused in this thread. A lot of this is to do with the traditions with toy soldiers and model figures and besides their backpacks they do come with a lot of excess baggage. A big homo sapiens and a little homo sapiens standing next to each other occupy or occupied the same 1:1 scale world. So the simple trick would be to scale the life size figures down using your preferred ratio. Not that easy in times past but professional sculptors used calipers set to the proportion they wanted and more than often these were a step up rather than reduction. Nevertheless a simple flip and they could reduce a dimension from the real model (person) using a caliper. The trouble with a scale like 1/72nd is that the calipers would be working at their limit and apart from body height, shoulder width (general dimensions) and so on the rest had to be made up. Even with larger masters and pantographic reductions there was still a tendency to extemporise the features etc. Many of the sculptors designing the model figures were (and still are) self taught and often they were doing what was required of them with great skill. The trouble was they rarely believed in standardisation afforded by a scale except as one or two dimensions. Nowadays using a computer it is possible to scale a real human figure down to 1/72 scale model and the model looks puny with a tiny head in comparison with most plastic figures. There are lots of other factors but basically each manufacturer developed their style and scale(s) for 1/72nd scale figures which may have been carefully arrived at almost like a trademark or just arrived at. Those who have wide ranging collections will recognise certain sculptors working between manufacturers and their keynote scale. The Preiser sculpted figures of Revell are easy to pick out. Manufacturers that tended and tend to employ a range of sculptors ( inc computers) usually have more fluctuations of scale. The AB range (Fighting 15s now) of mainly WWII 1/72nd scale white metal figures show how consistent a range is when designed and manufactured by a small team.
Therefore size doesn't matter to me one bit but scale and style does when it comes to miniature figures. I think if a manufacturer produces figures in a range that look widely different then that is a mistake as far as I am concerned especially if they are also supposed to be compatible with other manufacturers products. I don't generally buy mistakes but occasionally I have tipped a set straight from the box to the recycling bin and PSR helps out immeasurably but seems to give a size that "condemns" a figure when a head swop could reprieve it. I suppose the bottom line is that I am looking for reasonably realistic figures that look good and are in scale be they 4' 2" or 7' 0" in height in their original human form. Some eras ( eg bladed weapons) I would afford more leniency to as far as scale is concerned and the two policemen show that they have fairly similar sized heads or we might be in danger of saying little people have little brains ahem etc.