Sometimes you have to stick to a design where fonts are not proportionally scale.
Let's say you need your H2 to be smaller and your P bigger, but your H1 and H3 are fine. With scales it's impossible to achieve.
Also in 90% of designs you need many differente font sizes between 12px and 24px in comparison to 30px to 72px.
So I always end up missing some in the small range.
It would be neat if we could design custom fluid fonts where the values are not attached one with another.
For example a size system I would like to make would look like this. Of course this should be converted in rems and be fluid via clamp calculations.
12 px
14 px
16 px
18 px
20 px
24 px
30 px
36 px
48 px
60px
72 px
Also one issue that scales have, as far as I know you will end up with sizes that don't land right on the pixel like 31.25px , 48.828px etc and browsers handle subpixel rounding bit different.