I wanted Chalmers too. (I'm a life-long Jayhawks fan) But his mindset last draft is understandable. Giddens has a lot of upside, and has potential to be an above average defender with high offensive capabilities.
Chalmers is a great player, and has a ton of tools, but it seems that he may have reached his peak. He's playing good now, but that's because he was already a good college player that did well because of fundamentals. Giddens is a raw player that still excelled in college because of his athleticism. If you add fundamentals to that, and teach him a team game, you never know what his ceiling could be.