I've been making a similar argument for awhile. With the libraries now available and high level tools (Python, SQL, Numpy...etc) we can build tiny applications (just a few pages of code) that are easy to maintain and do exactly what we need. So replacing the majority of PSSE isn't very hard. An entire EMS system is another game entirely. It's not just the algorithms, but the full integration with SCADA and other things that most companies don't want to get involved with (too much risk).
On a different note, how are you approaching sparse matrices in Octave? Also, I assumed Octave's performance would be a non-starter here for large models. Is it performant enough for you?
On a different note, how are you approaching sparse matrices in Octave? Also, I assumed Octave's performance would be a non-starter here for large models. Is it performant enough for you?