Start with Dust 4e1180e5 (2020-08-30), you can now do this like so:
-f, --filecount
Directory 'size' is number of child files/dirs not disk size
Example output:
PS C:\Users\Steven\AppData\Local> dust -f
577 ┌── Default
628 ┌─┴ User Data
629 ┌─┴ Edge
1,154 ┌─┴ Microsoft
1,901 ├── Packages
407 │ ┌── 41ad6w4a.default-release-4
493 │ │ ┌── entries
497 │ │ ┌─┴ cache2
573 │ ├─┴ 7eccqsn1.default-release-1-1597857941226
3,952 │ ┌─┴ Profiles
3,953 │ ┌─┴ Firefox
3,954 ├─┴ Mozilla
3,096 │ ┌── entries
3,100 │ ┌─┴ cache2
3,269 │ ┌─┴ 56uzf1ra.Sunday
10,341 │ │ ┌── entries
10,344 │ │ ┌─┴ cache2
10,428 │ ├─┴ 7nx7hnxa.68-edition-default
13,698 │ ┌─┴ Profiles
13,699 ├─┴ Waterfox
21,181 ┌─┴ .
Since this was just released, I had to build it myself with this command:
$env:RUSTFLAGS = '-C link-arg=-s'
cargo build --release