Ok so I'm a newbie and I've been using drupal for my attempt to build a social networking site for my guild. Here are some of my wishes for drupal.
1) Better and sexier themes. All the themes are for blogs. The only decent one is bluebreeze.
2) The ability to place blocks side by side in the centre content area. I think Mambo has this ability, I forget, long time since I used it. The left, centre and right blocks give the site a phpnuke feel and look. A way to move blocks around would be sweet.
3) More forum features. Post count, signatures etc.
4) Sexier user profiles right out of the box. I keep seeing post on how to make better user profiles, but its only the pros that get to have the fun.
That's all I can think of right now. Drupal is pretty good, active and helpful community, we're happy with it.