We are in the process of collecting requirements for one of the next versions of JDeveloper.
And we figured we'll give you a chance to tell us what you would like to see.
To make it interesting try and prioritize your request (since we probably won't be able to implement every little one of them).
Then post your list on this OTN thread.
Also please try and be specific - for example, instead of saying better documentation - tell us what type of docs you would like to see and what specific topics do you want us to cover.
Thanks for helping us create a better tool.
P.S. - if you are still on version 10.1.3.* you might be interested in the newly released 10.1.3.5 version of JDeveloper now on OTN.
Here is the Fix list.