Jim you know well that Sheffield believes the war to have been necessary and the army generally well and competently led.
By exquisitely selective quoting from a balanced article you have dishonestly tried to reverse its message.

Let me do the same.
Opening sentence,
"Douglas Haig was 'brilliant to the top of his Army boots'. David Lloyd George's view sums up the attitude of many people towards Haig and other British generals of World War One. "

" Haig's army played the leading role in defeating the German forces in the crucial battles of 1918. In terms of the numbers of German divisions engaged, the numbers of prisoners and guns captured, the importance of the stakes and the toughness of the enemy, the 1918 'Hundred Days' campaign rates as the greatest series of victories in British history.

Even the Somme (1916) and Passchendaele (1917), battles that have become by-words for murderous futility, not only had sensible strategic rationales but qualified as British strategic successes, not least in the amount of attritional damage they inflicted on the Germans."

Concluding paragraph
" He (Haig) encouraged the development of advanced weaponry such as tanks, machine guns and aircraft. He, like Rawlinson and a host of other commanders at all levels in the BEF, learned from experience. The result was that by 1918 the British army was second to none in its modernity and military ability. It was led by men who, if not military geniuses, were at least thoroughly competent commanders. The victory in 1918 was the payoff. The 'lions led by donkeys' tag should be dismissed for what it is - a misleading caricature."