Opera did something similar back in 2010 in v11 with the opera:config#UserPrefs|HideURLParameter configuration variable. I found I was wanting the URL information often enough that I turned the feature off. I wonder the old Opera team had any metrics they gathered.
In Opera 20 I haven't found a way to re-enable fully expressed URLs. They adopted Webkit, and stripped out most of their configurability that was previously available from opera:config.
