Like any other man out there, I too was enamoured by Major General Maximilian Veers exploits during the Galactic Civil War as a 15-year old boy. General Veers always fought at the front, he wasn't involved with any of the racial and genocidal aspect of the war that was happening elsewhere in the galaxy and General Veers always appeared to me as a true gentleman rather than a hardcore Vader follower and the best general that Vader ever had at his disposal.
Recently however, I've been reading that Veers wasn't as talented as the history books I grew up with told me and that the major reason for the Imperial victory was surprise, shock and weak rebel forces. Ecca Nurt in his "A People's History of the Galactic Civil War" also points out that troops under General Veers' command committed atrocities against surrendering rebel forces - a view completely opposite to the "war without hate" which I have been seeing the battle of Hoth as.
How much of this is contrarian nonsense and how much of this is true? How good of a general was Veers and how did his talent affect the outcome of the battle of Hoth?
The Battle of Hoth was a very one-sided affair. While the Rebels were well entrenched and had taken some defensive precautions--the ion cannon and shield generator in particular--they were not prepared for an all-out assault by Vader's Death Squadron. So, Veers needed little genius to pull out a victory there.
Veers was instrumental in the design of that generation of AT-AT walkers, which were crucial to the land assault. He also attempted to remedy the walkers' weakness (their long legs), but his tactic was rebuffed by superiors--which resulted in far greater losses than the Empire should have encountered. This was actually Davin Felth, and Veers dismissed his concerns and had him transferred to hide the weakness. See /u/BassoonHero's comment for more.
As for mistreatment of the prisoners: I know of no evidence for this. Now, Rebel prisoners were often horribly treated by the Empire, but this mistreatment, if it did occur for those who surrendered at Hoth, was likely at the hands of interrogators, not front-line Imperial Army and Stormtrooper regiments.
First and foremost, I would like to emphasize that my successes would not have been necessary had Admiral Ozzel not failed to properly deploy the Imperial Fleet. It is a testament, not to my brilliance or skill as a general, but to the tenacity of the Imperial Army that they fought with such ability on the frozen wastes of Hoth against the entrenched Rebels deployed there.
Any claims of atrocities are simply unfounded. War is war, and the facility on Hoth was a pure military installation. There were no civilians and any atrocities are often unfounded or exaggerated. Hoth was, by the standards of the Galactic Civil War, almost bloodless.
For a more detailed inside look into the thoughts, tactics, and history of the man himself, I highly recommend reading my autobiography, AT-AT at Dawn or my book on the tactics of armored units, Warning, Walkers!. In it, I discuss my development of the AT-AT walker design from it's earliest prototypes and use in the Insurrection of Zaloriis, to the failed Rebel attempt on my life on Carida, and to the various engagements in which AT-ATs have played a crucial role.
Source: I was there.
There's absolutely no evidence that Veers' men committed any atrocities against prisoners, nor that he was personally involved in committed atrocities. You have to remember that Hoth was an inhospitable planet, from both the environment and the wildlife. Wampa attacks were rife; there was even a sustained wampa attack inside the rebel base as the Imperial forces moved in. I don't doubt that some prisoners died, but given the terrible conditions on Hoth, it is a testament to Veers that he got so many out as he did.
Veers certainly deserves a great deal of credit for his role in the Battle of Hoth and the subsequent Imperial victory. For had General Veers not shown the cool yet effective leadership he presented that day in the face of a drastically different battle plan than he had prepared for, the outcome may have been far far different.
While I and many of my contemporaries would argue that Imperial Victory was inevitable with nearly 3/4's of the Core Fleet bearing down on Hoth, the incompetence of Admiral Ozzel and his decision to pull the entirety of the fleet/strike force out of hyperspace just beyond the effective range of the Rebel's shields is a mistake that cannot be ignored. That decision (which led to Lord Vader ultimately relieving Ozzel of his command of the fleet, where Ozzel subsequently killed himself in his quarters, in a way I can only describe as being "clumsy as it is stupid") could have resulted in casualties far greater than those we saw.
General Veers skillful decision to land his troops far beyond the reaches of the Rebel defense batteries, as well as initiating a forward assault with his AT-AT walkers rather than attempting a flanking or pincer maneuver, greatly contributed to how quickly he was able to overwhelm the Rebel lines and allow his reserves to drop in beyond the defensive perimeter (once he was able to destroy the Rebel shield generator) to take the Rebel base within hours of his landing. Not since the Republic defense of Kashyyyk during the Clone Wars had the galaxy seen such an impressive display of generalship and tactical suaveness that arose under very pressing circumstances.