With what I mentioned in my second paragraph in mind I leave an assessment of Humphrey's life to author Matthew Lewis who writes in his blog -
"Humphrey was a well-liked figure who was popular with the common man and retained sympathy for the House of Lancaster as the government of his nephew became increasingly unpopular and out of touch with the country. The policy of eliminating those closest to the throne thrust Richard, Duke of York to prominence as Humphrey’s natural successor, caused those who had looked to Humphrey for a lead to turn their focus from the House of Lancaster and made York, not unreasonably, frightened of meeting the same fate simply by reason of his position. Perhaps paranoia was a part of the makeup of Henry VI’s mental issues even at this early stage, perhaps the Beauforts were manipulating him to improve their own prospects or perhaps it was a little of both. Whatever the reason, it backfired on Henry and the Beauforts, dragging England into a bitter and prolonged civil war."
You can read more about the Duke of Gloucester in Matthew's blog here