Here's my idea.
replace 1DN with (exp level) DN , keep highest roll.
Linking it to unit level makes intuitive sense also, as this would make experienced units more consistent, which is when the glass cannon syndrome strikes hardest. (It's usually not a problem in the early game)
If this becomes too consistent or inconsistent for certain units : what could be done is changing it to a keep highest 2 dice, then divide by 2, or highest 3 and divide by 3. (If necessary, and this is put in mostly for counterargument's sake)
I think this would be a vast improvement over 1DN.
