Right, my comment about one-to-one fighting is based on what I've read of the NW Frontier (quite a lot of original accounts) and bits and bobs about the Sudan. On the NW Frontier the Pathans almost never stood to receive a charge, and if they did they would basically loose. They did launch charges, but these were almost always cut down by British fire. There are a number of occassions where small parties of British are cut off and cut up. From what I know of the Sudan again, in general, where the tribesmen did get into contact they were repulsed by superior discipline etc.etc. This may be herasy, but I know little about the AZW.
I think one needs to be very careful about bringing in game mechanics that are designed to emphasise one sides' abilities too much. Throughout history victories are often brought about by the application of appropriate tactics to a specific set of circumstances, or the opponents' failure to use appropriate tactics or a combination of both. Isn't it more satisfying to win because of superior tactics or spoting and exploiting a weakness than simply because you have loads more dice than the enemy?
Building in abilities that are too extreme takes away much of the fun of the game. The basic "6" for H-T-H appears to be given to trained, competant and suitably equipped men. There are loads of special rules that can be applied to H-T-H such as Bloodthirsty and Ferocious Charge to bump up a value, but looking at the BP core rules and LAOK the core value of 6 rarely moves by more than +/- 1 unless we're looking at cavalry.
So, at Isandlwana, for example, one reading in game terms could be the British player has deployed his line out in skirmish order with no 2nd line supports. However the Zulus get good dice rolls for movement, steamroller in before the British firepower has time to wear them down. The Zulus get bonuses for charging, possibly rear support and possibly a size advantage. The British get no closing fire, are at a disadvantage for being in skirmish order and have no supports. Pretty much game over with the rules as written. Good deployment and tactics and perhaps a spot of luck for the Zulu, poor choice of tactics from the Brits. Refight it with the Brits deployed in close order and with good mutual support and you might get a very different game.
As a final however, however, I will add, as I always do, that I think games are very personal and that if swapping values around gives you the feel for the game that you want, then go for it. But, I think there are probably other means of achieving the same result within the existing rules - appropriate numbers of Zulus, large Zulu units or small British units, scenario design, hidden deployment and/or movement, use of special rules or modifying command values.

