I don't really have a set order I'm reviewing my suggestions. I started with Lee because I figured he was the easiest. I feel that Howe is probably not going to be nearly as popular a choice as Lee (in fact, I don't think any of them are!) But, Howe does have some arguments going for him.
Howe was America's first real competition. He came from a military family, looked dashing in red and would arrive in the colonies in 1775 shortly after Gage and King George had managed to make a war all but impossible to avoid. I don't know if Howe would have been able to negotiate some semblance of peace, or if he would have had more success in getting an olive branch from the colonists. When he arrived, though, shots had been fired and there were bodies in the field; Gage had failed to quell the nascent rebellion at Lexington and Concord. So, it fell to Howe and a war council of British generals to regain the upper hand.
Which, despite what historians teach you, the British had, but also didn't. As I intimated in my first post on the subject, Howe had logistical problems. The divided loyalties of the colonists were a much larger problem for Howe, and once Lafayette and von Steuben joined Washington, the rag tag bunch of irregulars quickly was drilled into a formidable fighting force. One that no longer needed to win out victories through guerrilla means, but was able to meet and vanquish the British in open combat. On Sept. 24, 1776, after Howe had pushed the colonists out of Bunker Hill and began his campaign in earnest, Congress called on the states to support the Army, making this declaration: "Without a well disciplined Army, we never expect success against veteran troops... without a moment's delay, bend all your attention to raise your Quota for the American Army."
Howe's early victory at Breed's Hill, for example, was when he was still fighting the old Continental Army. They were bunkered down, and historians acknowledge now that it was a dearly bought victory. It was a victory, but some of the English blamed Howe for its cost. Not enough though, or at least, none who were influential enough. He received his promotion and become the commander.
By the summer of 1776, Howe and 30,000 men were in New York City, Wood also notes that Howe was also given permission to seek a peaceful deal. He did not pursue Washington as forcefully as he could have, perhaps with hopes that he could reach peace with the colonists. Much like Howe's actions at Bunker Hill, not every British officer thought this was a good way to wage war; Wood quotes Lord George Germain, head of the American Department, as describing Howe's strategy as a "sentimental manner of waging war."
With Washington forced out of New York, Howe chose to instead consolidate his position. Wood, and I too, note that Howe was yet again frustrated, both by his men and his superiors. Between British looting and Washington's victories at Trenton, the British could not capitalize on the momentum that Howe had bought them. Once Burgoyne failed at Saratoga, and the French threw their lot in with the soon-to-be Americans, Howe's moderate strategy, which hoped for reconciliation, was doomed to fail.
Howe remained a soldier to the end though, even giving orders during his retirement party to attempt to capture colonial forces. By the time he was withdrawn though, Gen. Clinton could not recover. The war slipped out of Britain's grasp due to Howe receiving conflicting orders, and perhaps his own failings. His actions alienated his surrogates, and the distance between himself and Britain also complicated matters.
Yet, he did force Washington into retreat. He did manage to turn Gage's blunder into a chance to maintain the hold of the American colonies. He had not much to work with, but he spent his treasure wisely. A more daring (or brutal) general may have swept the field with Washington instead of allowing for his retreat; Howe's efforts though forced America to form alliances and to form an army and navy. Even if Howe were not the greatest general, he was instrumental in America's development into the nation it would become.
Again, much of this is from memory. Where I used quotes, I have linked to the books I used as a reference. Where fact checking was required, I relied on Googling. I still feel bad for not considering Howe when I wrote the original post, but after thinking it through in more detail above, I think that maybe I was right not to include him. Then again, compared to Gage and Clinton, Howe did amazingly well.