re: #1: Reputation is probably my least favorite attribute of any web community. Reputation should mainly be earned, organic, and kept track of in the minds of the individual users according to their own metrics. If rep is given, it should be given unto discussion or content, -not users. Anything that is too "in your face" about letting a user's reputation precede their output puts the emphasis in the wrong place. I like encouragement and recognition of value, but I prefer Hubski's method of giving a handful of "spokes" before ceasing to count them any longer, and letting you badge a noteworthy comment or link.

re: #2: Personal opinion is that images next to usernames have always been extremely annoying and distracting. They also "define and box in" users prematurely in my mind. I much prefer getting to know someone over time via their posts than seeing a "Spock" image right off the bat telling me "Hey, I'm logical sci-fi guy/girl." Maybe it seems trivial, but I'd rather have to work to get to know you a bit.

That being said, I guess if the default was hidden it wouldn't be so offensive. But still...meh.

re: #3: I've seen this work to good effect in other places, -specifically certain subreddits on Reddit. Being that it inhibits the sharing of some types of media to some degree though, I wonder at its application site-wide on general interest forums like Hubksi or even Reddit. If I'm following someone who posts quality links, I find I'm not minding if they link to interesting content without much to say about it. But it's an intriguing idea. This is an area where I feel I could benefit from other people's perspectives.

re: 4: I think this is a fantastic idea right off the bat. Now I'm going to go try and think up reasons why it sucks, but it feels so right to me. (EDIT: Already found good counterpoints in the discussion. Still digging the idea though)