With the new SharePoint design, you can easily resize columns (although, that setting doesn't appear to stick). But for the title column, it appears you cant go any shorter than what appears to be a minimum width.
Is there a setting to change to either make this minimum width smaller, or wrap to fill the space needed? For example, if you have a list with even just letters as the title for each row, it appears it will still be about 450 pixels wide.
I do notice that this is depending on the viewport sometimes as well. But even when embedding a very simple list as a webpart into a new page, it takes up a lot of room, making the user horizontally scroll for content that would easily fit in the 'old' look.