Huawei is the latest manufacturer to introduce their UI on top of stock Android. Often device manufacturers do this to distinguish their phones with others, often these UI customizations cripple the stock Android experience. Whatever may be the reason these custom UIs are not going anywhere for now.
Huawei is going to introduce Emotion UI in their upcoming Android phones. What features the Emotion UI will have is not yet clear, but it will be released officially on June 9th. We will know at that time whether this UI is something to take notice or not. According to this post on mobile163.com the UI will be kept simple and smart and designed based on user feedback.
The first devices to have Emotion UI may be Huawei Ascend P1 and P1s along with Huawei D Quad.