This is a general reply to the whole thread, hopefully commenting on the cruxes of the conversation
As a preface I've noticed allot of references to an English army, I prefer British army from 1707 onwards as it's more accurate. This is just a suggestion not an attempt to give orders.
First. I did not read anything derogatory about Smith in the initial quote. When the author referred to a "species" all that means is he was saying a kind of guerrilla war, that is to say one that he considered slightly different from others. If Smith was sidelined in the book let us remember it is a book about the army, not the navy.
Second. I agree that Guerrilla warfare existed before the Napoleonic wars. In the 18th century, as has been noted, it was called Petit Guerre. The British Army had been roundly condemned in 1776 and 1812 for utilising the services of the American Indians. Wether we are now confusing light tactics with the irregular partisan movement, a large amount of low level operations had been mounted by Rangers and the like during the French and Indian War.
3rd Wellington took advantage of an already existing Guerrilla movement in Spain and Portugal rather than instigating it, and tried to coordinate/regulate it as much as he could with other Spanish armies.
4th I must say that The Battle of Maida, reads much as a tactical victory, but indeed if it not a strategic failure then certainly a strategic defeat. Much as Corunna was a tactical victory but a strategic defeat, the difference there being that Moore had to clear his rear before getting his men away. For the French any reverse was compensated by the withdrawal to Sicily. Almost exactly the same thing happened in Eastern Spain when the Anglo Sicilian force tactically defeated Suchet at Castalla but then failed to use his advantage and retreated to Alicante.