The team I work for is split between SQL Developer and PL/SQL Developer (Allround Automations); myself and another guy on my team are continually trying to find reasons to get the other (more senior) developers into trying SQL Developer.
It's an accepted feature and we do plan to do it at some point.
In 2008, we released 1.5 and incorporated many of the feature requests from the Exchange. In fact, SQL Developer 1.5 was primarily released to address feature requests. Our next major release is 2.0 and the focus of that release is the Data Modeling, which again was a request from the Exchange. If you sort the requests on the Exchange you'll notice that most of the highest weighted features are in a release or scheduled for a release. I understand that time passes and we seem to have overlooked your request, we have not. There are many factors involved when adding features to a release and to releasing products. Even features scheduled for a release may be withdrawn if they are not functioning as we would like. It's a balance. Even now there are features in the product which provide enough functionality for some people while others say they should not yet have been released as they're incomplete.
I should also add that SQL Developer is aimed at the database developer, so features that might be deemed to be DBA-type features, are not currently high priority, as Oracle provides Enterprise Manager for that audience. Where your votes are then crucial to us is that we can take the top ranked features to the executive management and we have evidence they're highly desired within this product. Just yesterday we spend a little time reviewing requests and we start by ranking them on your votes. This is why we ask you to vote on existing ones and not to raise new duplicates.
Your input on the forum and Exchange has been really useful to us, and I hope you can continue to realize it's benefit.