I think this is a hangover from Battleground. The idea being that horse artillery due to it's tactical flexibility was more capable in close. There are some examples of this in history actually. Was it Mercer at Waterloo who blasted the French cavalry to a stand still by double shotting his guns.
Bill I am not sure that Canister was as ineffective as you say. Most of the times I think tactically the infantry would avoid a run right into the head of the guns and would move slightly to the flanks.
Canisters fan out effect was designed to counter this problem and allow the gunners some better close in defense. But I would say a direct frontal assault of an artillery battery at close range would produce some pretty horrendous casualties. This was certainly the case at Borodino for example.
At Wagram there was a lot of space to manuever this tends to counter the artillery threat once units got close also I think the Austrian artillery was some of the worst trained of the Napoleonic wars.
Borodino was more of a bottleneck situation hence the massive casualties that day that exceeded even the Somme as a proportion of combatants.
The close in use of artillery often proved quite decisive in the N wars. The unveiling of the French 12pdr battery at one point on the Pratzen is one possible example, or the French artillery at Friedland and the Russian grand battery at Eylau. The latter virtually eradicated an entire corp that stumbled out of the mist to be in front of a 70 odd gun battery.
I believe in HPS it is to easy to frontly assault batteries mainly because the attacking force should really have an automatic morale check for such action and this does not occur.
A historical example of this is the French assaulting the great redoubt at Borodino. They had to try numerous times before finally succeeding. The effort was pretty huge and included using massed cavalry.
I recall the redoubt was garrissoned by only 18 guns I may be incorrect on that. Compare that to the resources the French tossed against it and you get an idea as to how effective artillery close in could be.
At Waterloo there can be no doubt had the French pushed forward more artillery with their cavarly assault they would have done some pretty terrible damage. As it stands I think it was only 1 horse battery that got forward and it's effect was devastating.
This decisive influence of artillery up close at Waterloo is further illustrated when the Le Haye Farmhouse fell and Ney brought a battery up into close range threatening the British centre. At this point the whole allied line wavered and it was really the moment that prompted Wellington to describe the battle as 'a near run thing'.
Artillery was the decisive weapon I think in the Napoleonic wars and prompted N to say 'it is with artillery we make war'
I am happy with its representation on offense in HPS but on defense I believe it is lacking not so much due to casualites it inflicts (assuming it fires) but more due to the lack of morale test on the attacker
Just my 5 cents Bill.
Salute
General de Brigade Knox
Grand Duc d'Austerlitz et Comte de Argentan
Escadron Mamelouks
Chasseurs a'Cheval
Division de Cavalerie la Vieille Garde.
CO. 1er Brigade, II Heavy Cavalry Division, Reserve Cavalry.
http://www.aspire.co.nz/colinknoxnwc.htm