1) The way the new inboxes look only about 1/4 of my screen is used to read emails, and i usually have to scroll up and down, and also left and right, just to read them. This is ridiculous, please devote more of the screen to the actual emails please.
2) What is with the Starred/Contacts/More panel on the right? It contains absolutely nothing and is literally useless. Delete it, or please give us the option to hide or minimize it.
3) Eliminate the tabs, I hate them. Show me my entire inbox, or give me the option to choose which tab my email automatically defaults to when I log in. All, Primary, Offers, Social, Newsletters - this is completely unnecessary.

If you are trying to drive me away from using all of yahoo's services entirely you are doing a great job at that at least. I HATE EVERYTHING ABOUT THIS NEW FORMAT.