As a brewer that competes, you know that the brewing landscape is changing. How many new styles have you seen made by home brewers in the last six years? It'll continue to change and grow after these guidelines are released.
The BJCP guidelines need to reflect the changes that exist since the last release. The operative word is "reflect." The BJCP is not, nor ever has been, a complete source of world beer styles. It's a reflection of what is available commercially and what home brewer's enter in competition.
This set of guidelines is trying to include our brewing brethren in Australia, NZ, South America and Europe, where BJCP exams have been given and there is a growing pool of judges. The new guidelines reflect styles and ingredients that are popular in those regions.
At it's most extreme, every single beer brand could be considered a "style." After all, they all taste different to varying degrees, right? But, that would turn competitions into cloning events and awards into participation ribbons. That's not only impractical, it's no fun, either.
OTOH, look up some of the older versions of the guidelines. The styles were much more confined. The 2004 version was a big change from the 1999 style list and had much deeper descriptions.
The earliest guidelines were nothing more than tasting notes that worked best if you'd actually tasted a fresh example. There were very crude stats on the last page.
http://www.bjcp.org/docs/1997_Style.pdf