I've used Oracle*SDE and Designer, ERwin, and other ER modelling tools. These tools did not make life easier when doing the initial design. In fact, they often slowed me down, as I can usually stream-of-consciousness code faster than design and code. But nearly all (of my) code eventually needs upgrading or troubleshooting, and SOC coding is a royal pain to debug, since I probably can not remember how or why I did something. So I learned from experience that I should design first, then code.
Emphasis on 'should' - the sheer weight of most of the modeling tools encouraged a prototype first, or SOC programming, attitude.
SQLDeveloper, based on the JDeveloper's extensible framework, is an exciting product. Fairly easy to use, SQLDev is definitely in conflict with Oracle's traditional NUIs (Non-Intuitive User Interfaces).
In this session, we got a heads up for a graphical ER tool extension to SQL Developer, including relational and multi-dimensional modeling. With a distributable 'viewer', and eventually a database-based repository. Some subset of the demoed features should be in public beta 'Real Soon Now'.
When I worked for Oracle, a number of us were privileged to use the ARIA project built on an early internal release of HTML-DB. So when Oracle released HTML-DB as a 'feature' of Oracle8i that peaked my interest, especially as a possible replacement and consolidation for the myriad of small Access, FoxPro, DBase personal databases that was proliferating. Unfortunately, Portals were the flavour of the year, and it seemed that HTML-DB was sidetracked as the Oracle Portal took precedence.
Fortunately Oracle came to their senses
The SQLDeveloper extensions - such as those which understand Application Express and that provide ER modeling - have helped make SQL Developer one of my favorite database access tools in Oracle. Between SQL Developer and APEX, I suspect I could spend a lot of my life learning features and futures such as the ability to use the Oracle Forms XML definitions to initialize new applications, and unit testing made simple (with check-boxes to define limit testing), and ...
I'm looking forward to the day when SQL Developer includes extensions to administer Oracle Warehouse Builder.
For now, I'll be keeping a closer eye to Eddie Awad's blog at http://awads.net/wp/ and Sue Harper's at http://sueharper.blogspot.com