To me it is not only the size, I love my 12 Mini. But more than that is the weight. WTF does Apple think making the Pro line heavier AGAIN. The normal 13 Pro weights almost as much as the big XS Max did. WTF. Really, I am shocked. Do they want to get people to buy he normal 13 because the Pro weight is too high? Over 200g for a 6.1 inch model when a 6.5 inch model with same materials wasn't heavier.
I had the 12 for a while and I could get used to the size, also I would never trade it for my Mini. But the weight is what always bothered me with the Pro iPhones. This was ok with the 12 but not with the 12 Pro. When holding the phone longer, THIS is what you feel and what is bothering you, not so much the 6.1 size.
I would rather buy the new normal, cheaper 14 Max, if rumors are true, than the 14 Pro smaller size. Just because of weight.
For me the 12 Mini, 13Mini someday next year, will be my main device for a long time. And I have always bought the latest and greatest, and most expensive. Till the 11 line.