Personally, I think that the tags block in the new post is a step back from what it was. No add tag button, and the tags are not managed as they were in 2.6.x. Please tell me that this is only a design flaw and that it will be corrected upon release!
A screencap of the New Post screen: http://www.flickr.com/photos/tsjessica/3098487776/
Edit: This is a screencap of the Edit Post screen: http://flickr.com/photos/tsjessica/3098909784/