Only if you have all these features can you adequately organize all kinds of information, not just a specific kind.
Yes Ecco is/was an excellent outliner+data grid, but had no item to item linker, and forced structured tree representation, which may or may not suit the specific information or the way a particular person wants to work/organize its information. It had rich text outlines and customizable UI but for the rest, the above features were not great or not there at all. If Ecco-Ext is an amazing effort to bring a second life to Ecco, even with Ecco-Ext, most of the above features are missing.

SQLNotes development started 4 years ago and is now in beta tests. It takes the best of Ecco, and improves upon it, taking the concept much further. It has ALL of the above features.

The current beta available at http://www.sqlnotes.net is very stable. You are all welcomed to download a free copy.

That said, I was a user of Ecco back in the day, and I’m not sure that OO can truly replace it across the board. That’s not to say people aren’t trying; OO is being used as a platform for a variety of things, including implementations of David Allen’s GTD cult. It doesn’t have built-in PIM functions, though; it’s just a powerful outliner with scripting support.

One of those program names that doesn’t exactly reach out beyond the geek crowd, though :-)

What would be harder — and I think this is where Chandler came unstuck — is to fill in the missing bits of Ecco’s functionality, which are, essentially Email and other message hoarding. When the program was first released, keeping contact records was really a matter of writing down what people told you on the phone. Things are more complicated now. Most of my contacts with anyone today are electronic, and to keep up the usefulness and intuitive simplicity of Ecco there, it would have to handle email. That isn’t trivial.

Curiously, Eco’s calendaring and workgroup functions still seem entirely fine to me. In any case, it wouldn’t be much of a stretch at all to synch Ecco’s Calendar with Google’s. There are apis at both ends. It is sad that this is what Chandler ended up doing.

One of the things that first interested me (and a lot of other people) about Chandler was its free-form-PIM concept (inherited from Lotus Agenda), though the product gradually evolved away from that idea. And the lessons learned from observing the Chandler story, to me at any rate (the danger of investing too much in reinventing a back end and building from scratch, the possibility that new trends like web-based applications will overtake your plan if you delay too much, etc.), are very much in sync with these observations about Ecco.

More recently, anyone developing in the PIM space is doing Web-based stuff, mostly. Someday I think someone will do a Web-based Ecco and it will be astonishingly useful. (Backpack is fun but nowhere near as versatile. Jotspot looked like it was heading in the right direction, too, and now it’s part of Google, so we’ll see where that goes.) So, right, waiting for an open source version isn’t the “only option,” but the other option — building an Ecco-like client-based program from scratch — just seems highly unlikely. Though what slangmgh is doing suggests that his alternate route — of not building from scratch but radically renovating from the outside in — might prove surprisingly effective.