I don´t dislike the new UI but there are 2 things that bother me quite a bit. The first is having to press a button to see my exact stats such as AD, AS and AP. It is bound to the C key by default, but since I already bound that key to a different skill I have trouble easily bringing up the stats to see what I should build.
The second problem is jungle related. As a jungler I am used to checking a teammates mana and health right before I gank for them. But the mana bar is slightly to small and not easy to see in just a glance.
The solutions I came up with is a way to permanently show your stat screen instead of holding a button to see it. You could also adjust the opacity so it doesn´t hinder your vision too much. The second is making the mana bar slightly thicker than it is right now.