The Story Editor is not the "default tool for editing text", it's just the one you used because you didn't know about the Properties Palette and found the Story Editor by experimentation, and that's the problem. [What follows is purely my own opinion and should in no part reflect badly on any other forum user.] To paraphrase what a.l.e quite rightly said: The PP should be visible by default and should be displayed every time Scribus starts up so that every new user knows it exists. Scribus is practically useless without the PP so it should always be displayed unless the user decides to close it, even though I can't think of a good reason why someone would want to keep closing it.
The Story Editor has some uses in very specific circumstances but, for the most part, it is confusing and pointless. I believe it should be kept because it can sometimes come in useful but it should not be as prominent as it is.
I have never used the "Attributes" myself apart from with TOCs. I have no idea what other uses they have and they are not sufficiently documented anywhere that I can find. I have no idea what the parameters are used for or how the relationships work and I'm guessing that the vast majority of Scribus users are in the same boat. Aside from TOC-use, as far as I can tell, Attributes are a feature waiting for a use.
a.l.e has also mentioned that there are some "loud" people who - for whatever reason(s) - are resistant to making certain changes to Scribus, changes that would make the software look better in the eyes of most people and make it more usable. I have encountered this first-hand and it totally baffles me as to why they are acting this way. It's almost as if they want the project to look bad. This forum and the bug tracker - and probably elsewhere too - contain many very good suggestions for making Scribus look much better by simply making tiny changes but some people seem to be deliberately against making these changes. Whether they think that Scribus is their own personal playground or whether they are merely using Scribus as something to put on their CVs or to show off to their friends with, I don't know. These people are both taking the project forward - by maintaining the code and adding new features (in the developmental version) - and holding it back - by deliberately ignoring popular suggestions and not having a new stable version for more than two years - at the same time. Baffling.
The Scribus project has great potential and it could have been much more prominent in the minds of the public but the way certain people in the project have conducted themselves has held it back and led it near to the point where it could be on the verge of being irrelevant for a lot of people. Until later this year, the only "real" competition for Scribus has been InDesign and QuarkXpress but there's another application coming soon which - if it performs as well as its sister products and at a similar price - will, for Windows and OS X users at least, simply be a "no-brainer" option. I believe that once this new application has firmly embedded itself in the DTP arena, the Scribus user base will drop off considerably (except for Linux users).
Many people have done great things with Scribus over the years but I'm afraid that, if the attitudes of some people connected to the project don't change soon, the project will spiral down to the point where it is merely a quirky toy that's maintained by a very small group of people for their own entertainment rather than being a respected application with a keen and vibrant community. That would be a very sad state of affairs.
It's also worth noting that, as Scribus is open source, there's nothing to stop another group of people taking the code and making their own version with all of the annoying little quirks removed and the major bugs fixed. It's just a thought...