It's a disappointing end to the year for Katie, but to put things into perspective she has amassed 107 points from her top 8 tournaments post-Wimbledon, an average of between 13 and 14. Extrapolated to a full year that would put her at around 150 in the rankings, which is a considerable improvement on any stage prior to her grasscourt season breakthrough.
To reach the top 100, however fleetingly, before her big grass points fall off, she needs to average 15 to 16 points from her other (15) scoring tournaments, so she only needs a small improvement in the early part of next year to achieve this.
A big plus for Katie is her mental strength when things get tight - she has won 8 out of her last 10 3 setters.
I agree that it's always tempting to get a bit over-negative after runs like this. Whenever a player breaks the top 500 we get annoyed if they struggle to break the top 200. When they do break the top 200 we get annoyed if they struggle to reach the top 100. It's natural.
While we're all disappointed that Katie has performed badly recently, it's worth remembering that she remains in the group of brits who are challenging for the sort of level of achievement that we haven't seen in the ladies' game for a while. I personally think that Cavaday is the one most likely to progress, but I'm sure Katie, Anne, Bally, Anna Fitz etc are doing their best to prove me wrong.