I've been thinking about the User Interface more, and aside from minor tweaking that I'm sure they will continue to do, Its starting to grow on me for sure.
I think its a smart move to simplify the U.I. a bit, make it easier to find things. The only problem I had with Reach's UI was once you went into the sub menus and options the visual hierarchy started to fall apart.
I couldn't find a better picture to demonstrate what I'm talking about, but in the Social settings, things like Motivation might be the filter you are looking for, but its the same size as the specific mode of motivation listed. This gets to be a worse problem in the menus for altering controls, files, map files, game play files, you name it.
Now with Halo 4's UI, or should I say the work in progress build we have seen so far, I'm starting to like what I see.
Here is a video of some of Halo 4's UI http://www.youtube.com/watch?v=NBg9DypNb9M&feature=player_embedded
Now the guy gets caught up looking at armor towards the end of the video but I think we can extrapolate a couple goals from what we have seen so far.
-Halo 4's UI elements are larger, less negative space
-An emphasis on showcasing a players "Spartan", instead of their emblem.
-Compared to Halo Reach's almost exclusively text based UI, Halo 4 relies more on icons.
What jumps out to me at first is Halo 4's UI, in more ways that Reach, moves horizontally instead of vertically, This makes sense given the way an HD Tv is proportioned. When you put things from left to right, you can display them larger, and more importantly, display their spartan. This has to be the reason for this particular choice, otherwise why make a spot for their name and emblem that large? Its nice that people will more easily be able to view your spartan now, although it wasn't much harder in Halo Reach.
Overall it seems the User Interface has a lot less breathing room, something some people here obviously either don't like, or its a big change from previous Halo games.
The larger emphasis on horizontal movement is refreshing too, in fact, one of my favorite elements of the Reach UI design is how if you say, hovered over someones name, or went from the "game options" over to the player list how the screen would orient itself in a slightly different way.
I don't really understand a majority of the UI complaints thus far... most of it just seems like people complaining because its different, not because its poorly designed.