I am a BA in history as well. I don't believe the Tudor propaganda nor do I believe the Ricardian view that Richard is some misunderstood saint. Negatives about him were being started before Henry returned to England, he just built on what was already out there.
True, BUT the path many of the negative rumors took followed the travels of one John Morton, close confidant of Margaret Beaufort and later Henry VII's chancellor and Archbishop of Canterbury. Shortly after Richard was crowned, Morton and Margaret Beaufort were implicated in an attempt to "rescue" Edward IV's sons (who were possibly not meant to survive) and Morton was put in the custody of the Duke of Buckingham (and Margaret into her husband's custody, bad move Richard) - and the rumors of the boys' deaths started near Buckingham's estate. It was after this thwarted "rescue" that the boys were probably moved out of London. During Buckingham's rebellion later that fall (was Morton using him to prepare the way for Tudor?) the bishop escaped to France and hey! what do you know, rumors that the boys were dead started appearing in France.
As Henry VII's chancellor Cardinal Morton was the inspiration for the "Morton's Fork" taxation policy: "If the subject is seen to live frugally, tell him because he is clearly a money saver of great ability, he can afford to give generously to the King. If, however, the subject lives a life of great extravagance, tell him he, too, can afford to give largely, the proof of his opulence being evident in his expenditure." Henry VII took in a lot of taxes! (And managed to financially cripple much of the old nobility in the process...) And of course, the Star Chamber attained its sinister reputation under Morton & Henry.
Cardinal Morton also had a young man in his household, seven years old in 1485: one Thomas More. It is believed by some scholars that the "History of Richard III" attributed to More in the 1520s was actually written mostly by Morton. Oh, and did you know that Cardinal Archbishop Morton's nephew was in charge of the records in the Royal archives in HVII's reign? The same archives that are mysteriously missing most of the documents that would have existed for RIII's reign? Including the minutes of the council meetings that resulted in Richard being offered the throne by the council and Three Estates? and the evidence proving Edward IV's marriage to Lady Eleanor Butler, parts of which were detailed in Titulus Regis? Coincidence? And no, I'm not a conspiracy theorist, but if it looks like a duck, walks like a duck and quacks like a duck... Well, history has been written (and re-written) by the winners as long as humans have been around.
Before the death of Edward IV Richard had a sterling reputation as an excellent soldier, and a fair and just "Lord of the North" known for his loyalty to his family. Was he a "saint"? Absolutely not. Not even most of the members of the RIII Society go that far, media reports to the contrary (and no, I'm not a member of the Society although I do read, but not post on, their forum.) If you strip away the Tudor myth and look at the pre-1483 sources Richard Duke of Gloucester comes across as a decent, pious man who just wanted to live his life in service to his brother in the North where he was loved. Circumstances placed him on the throne, and while that may have changed him I can't believe his character would change that drastically in just a few months to that of the Tudor monster. During his reign, some of his laws included the institution of bail, creating a form of legal aid for the poor, lifting the ban on printing books, and requiring that laws be published in English instead of French or Latin. He also had the remains of soldiers killed during one of the battles of 1471 (which one escapes me at the moment) exhumed and reburied in consecrated ground - from BOTH sides. He also had Henry VI reburied in St. George's Chapel, moving him to rest in royal ground. All of this was similar to the kinds of things he'd been doing all along in the North. He hadn't changed.
Sorry for being long-winded...