Hi Groslau,
The variable +1 +2 or +3 is there to ensure that so called Veterans cannot 'bank' on a fixed bonus every time. We have found it works pretty well and represents that they are better but just how much better??? than others. The malus for Recruits works the same way. It takes out freak results.
Shooters ALWAYS have at least 1 shooting or combat dice no matter how bad things get. That is stated in the rules. So even a moving Marie Louise column of attack at 27 inches distance should still shoot as it will always get 1 die.
Having played very many times and with very many players I can reassure you that it balances out pretty well. If your pair of Skirmishers get:
1 die
+ D3 Vet = 3
+2 dense target
that would give a mighty 6 shooting dice but of course:
They would need to be at a range of 3 inches, not have moved more than half their move, not on WAVER. It is possible, not common.. if it happens just call them Sharpe and Harper!
British skirmishers only get the Vet bonus if they ARE Vets. The shooting bonus for not Vet British is only for close order battalions in line.. hope this helps