Typed up on mobile so I'm sorry for any spelling errors I didn't catch.

I'm actually reading a biography of Washington right now.

Washington does not have a great military legacy if you look at the details. He did not win a single engagement during the French & Indian War and was the mastermind behind the disaster called "Fort Necessity". He picked a flat, muddy plain to build a ramshackle fort against a vastly greater French force. The resulting attack and unfortunately timed storm had his men knee deep in mud with soggy guns that could not fire at an enemy experienced in woodland combat. He surrendered, but was allowed to retreat with his surviving men.

However, his legacy was saved by his friendship with the Royal Governor of Virginia at the time. Instead of being recognizing as a bumbling, young commander, he was hailed as a hero who made a gallant stand against overwhelming odds.

His heroism built from there and by the time the Revolutionary War began, he was given the title of General of the Continental Army.

I won't go into crazy detail, but he did an okay job. He lost as many engagements as he won and often his inability to adapt a battle plan was his undoing. When everything went according to plan, he was an efficient General who executed well. However, if a battle went awry or circumstances changed, his decision making fell to pieces.

The Battle of Philidelphia is a classic example of this lack of flexibility. He overlooked a chink in his defensive lines which British and Hessian forces took advantage of, moving a large force onto his flank and exposing his entire army. Though he received reports of such a movement, he did not answer fast enough or seriously enough until it was too late.

This is not to say the Legend of George Washington the General is a sham. It isn't.

What Washingotn could do was keep an army together. He was an inspiration to his men. A self-made aristocrat from Virginia who spoke to Southeners and Northerners like brothers (though he harbored a distaste for "the common people" throughout the war). He was magnanimous, he empathized with his men, was the icon of the a united nation before it even had a name. People saw him as a national hero, rather than a brave Virginian.

He was called the American Fabian. He knew to defeat the British Army, the Continental Army needed to survive more than it needed to win. Fabian was known for constantly skirmishing with small detachments and evading head on engagements. Washington emulated this against the British to great effect. Outside of combat, he held the army together where no one else could. Even if he was pressed to the edge multiple times. Despite enduring hunger, dishevelry, lack of ammunition, constant turnover, a divided idea of citizen (colonists, slaves, etc.), debilitating defeats, treason and betrayal, Washington held the army together through the seven long years of the war.

Now, his peers had a less than stellar opinion of him. His nearest agents, those directly involved in his day to day affairs, adored him and saw him as a hero. Other Generals and commanders across the colonies saw him as bumbling, inexperienced, clueless, and man who was far less than the myth.

General Gates was his arch rival, making overtures to replace him or boot him out of his command all together, a possibility that was too tangible for the mid-years of the war.

Gates conquered Fort Saratoga early in the war. A dramatic and unexpected victory, it blew the British and Philidelphia Congress away and Washington was nothing but envious. He was glad for his country, but it was the sort of victory that eluded him. Gates was dismissive of Washington throughout the War, even after he met his own disgraceful fate.

There was a very real conspiracy to unseat Washington throughout the war. For his lack of military success, more military minded men saw him as the aloof man that Gates saw.

Benedict Arnold, a trusted friend of Washington's, was hailed and adored by Washington. Little did he know, between almost losing a leg, being passed over for command positions, and his own role in the Battle of Saratoga being overlooked, Arnold despised Washington. Benedict Arnold went so far as to attempt to deliver Washington into the hands of the British before his treason came to light. A chain of happy accidents was the only thing that stopped this from happening.

I'm rambling a little, but he was not seen as a military mastermind amongst his peers and friends. His detractors saw him as a clueless General hanging on phantoms from there French and Indian War, his allies saw him as a beacon of inspiration for a nation hungry for freedom, which he was.

TL;DR: He was seen as a great, self made man who embodied the ideals of the new nation, but contemporary generals saw him as a bit aloof and inexperienced without a great bulk of military victories to justify his position as Commander of the Continental Army.

EDIT: Fixed some words