John, I do see your point in the differences as to what happens when searching vesrus clicking global tags, but those are two very different functions. 'Searching' is not 'looking for related blogs'.
When you search for 'conservation' you are looking for the appearance of the word 'conservation' in the post content of a blog on wordpress.com. That is why you get a list of results with 'conservation' highlighted.
When you click the tag/category named 'conservation' you are looking for other blogs who also use that tag/category. The word 'conservation' may not even appear in their post, but they are using 'conservation' in their tags or categories. The list of results will be totally different, and there is no need for a search bar because you are not searching as such.
That said, I fully agree with you on the now news-like look of the home page, which personally I think is a better design for highlighting blogs and posts on wordpress.com, but it does not tell you that wordpress.com is all about blogging and about community. That is the core business of wordpress.com and it really needs to be mentioned on the front page. I second that. That's why I alluded to http://www.typepad.com in a previous comment in this thread. At least you know the instant you read the front page there that it is about blogging. With the new wordpress.com, if I wasn't already on there, I get the feeling of a social community site at best, but not somewhere where I can make a blog.