Representing the largest overhaul in it's 53 year history, the Recording Academy has announced that it is eliminating 31 categories effective with next year's awards.  Pop, rock, country, and R&B were hit the hardest;  Gender-specific Grammy's will no longer be handed out.  Instead, a "best in" winner will be announced.  Also - several ethnic and specialty categories will be grouped together.

The most noticeable changes are in the stripping of gender-based categories in pop, R&B, rock and country. There will no longer be separate awards for male or female vocals, simply an award in each genre for a single "solo performance." Several instrumental categories have been eliminated as well.
"Every year there are changes but we've never … stopped and stepped back to look at the whole thing," Portnow told Billboard in an exclusive interview. "[We asked], is there an underlying infrastructure and rationale across all the awards as to how we're doing this? And what we found is, there wasn't.
"So we said, 'All right, let's deal with the holy grail here. Let's sit down and talk about what might be a vision or an overview structure of this that gives us some consistency.'"
In addition to the category alterations, the Recording Academy has written new rules on entries and voting. Each category must have at least 40 artist entries to move forward. If a category receives between 25 and 39, only three recordings will receive nominations.
If there are fewer than 25 submissions, the category will not be presented. The category will be discontinued if there are fewer than 25 entries for three consecutive years.

Grammys Announce Broad Overhaul of Award Categories | Billboard.com.