In his essay in the back of this year's annual, Russell Carlton posits that by having to write about analysis every day, it's made the product weaker. You can't write new, cutting edge analysis on a regular basis. You've got to come up with a hypothesis, gather data and then test it. Or for those articles that are less quantitatively based, it's nigh impossible to write a fresh piece everyday (Gary Huckabay, Joe Sheehan and Steven Goldman did an awesome job with their daily writing, but even the three of them had their usual topics that they hit over and over again).
BP burst upon the scene in 1996. I discovered them in 1999 when Rob Neyer touted them in his ESPN column. Absolute intellectual and analytical heavyweights wrote for the annual and the website over the years: Gary Huckabay, Joe Sheehan, Christina Kharl, Nate Silver, Steven Goldman, Jay Jaffe, Kevin Goldstein, Voros McCraken, Will Carrol, Keith Law, Jonah Keri, Rany Jazzeryelli (I never spell his name correctly) and a host of others. Sadly, they have all moved on to other things (the brain drain was especially strong over the last 2 1/2 years).
The first 10 annuals had new essays with all kinds of different findings and theories. The essays disappeared (they are back, but alas, there are only 2 of them). The player comments have grown shorter, less biting and less analytic. The team essays were usually stellar, but now they have been diminished as well (they are much shorter and basically a summary of what happened in 2012).
BP was small and had a hard-core, very bright readership that watched a lot of baseball. As they've grown, their best people moved on to try on new things and make more money. They had every right to, and it is ridiculous to think that those giants would be easily replaced. Readership has expanded, and BP focuses more and more on fantasy every year (which is fine, but some fantasy players watch very little baseball). They used to be baseball outsiders, but because of their great insight and analysis, they became baseball insiders. And then they grew less snarky and less analytical. The business model of BP has been a success, but the product has suffered. It's a real shame.
The annual is still good, and probably better than almost everything else on the market, and I'll probably continue to buy their products. Until something else comes along.