IMO "weaving through traffic" is not a skill that makes you a good driver. It might take skill, but it's irresponsible and reckless. A good driver understands that weaving is more likely to result in injury, property damage, or no result (think of the lane-switchers in rush hour traffic that you end up right next to after 30 mins) than an actual benefit. I'm not sure that it should be included in a confidence measure for driving ability.
I'd disagree - lane switching is not weaving though traffic. In advanced motorcycle training it's called "making progress". It's a skill to read the traffic flows, to understand what other drivers are going to do, the ability to anticipate what manoeuvres they will perform. You have to read and understand that flow, plan a route that gets you through the traffic safely and project far enough ahead to adjust to variations as they occur. So yes it is a skill indicative of a good driver, those "lane-switchers" that end up right next to you after 30 minutes are the ones who lack the skill to read the road far enough ahead. IMHO of course :)