I completely agree. The unpredictable outcome of infantry engagements is a serious issue that adds nothing but frustration to the game.
Unpredictable how?
Unit in better cover wins.
If not, unit with better weapon/armor wins.
If not, unit that hit with nade wins.
Rifles win over SMG at long range, loose at short range.
Scripts equal grenadiers in same cover, grenadiers got advantage in heavy cover when both squads are in one.
No rocket science here, no randomness.