This reminds me of Joel Spolsky's "Bloatware and the 80/20 myth": http://www.joelonsoftware.com/articles/fog0000000020.html , in which he says:
A lot of software developers are seduced by the old "80/20" rule. It seems to make a lot of sense: 80% of the people use 20% of the features. So you convince yourself that you only need to implement 20% of the features, and you can still sell 80% as many copies.
Unfortunately, it's never the same 20%. Everybody uses a different set of features. In the last 10 years I have probably heard of dozens of companies who, determined not to learn from each other, tried to release "lite" word processors that only implement 20% of the features. This story is as old as the PC. Most of the time, what happens is that they give their program to a journalist to review, and the journalist reviews it by writing their review using the new word processor, and then the journalist tries to find the "word count" feature which they need because most journalists have precise word count requirements, and it's not there, because it's in the "80% that nobody uses," and the journalist ends up writing a story that attempts to claim simultaneously that lite programs are good, bloat is bad, and I can't use this damn thing 'cause it won't count my words. If I had a dollar for every time this has happened I would be very happy.
When you start marketing your "lite" product, and you tell people, "hey, it's lite, only 1MB," they tend to be very happy, then they ask you if it has their crucial feature, and it doesn't, so they don't buy your product.
Wordpress seems to have everyone's critical feature, or critical plug-in, or a developer intimately familiar with the platform who can be hired to write your critical plug-in. By the time "more specialised blogging engines" have the flexibility and pervasiveness of Wordpress, I bet they'll resemble. . . Wordpress.
