I think it looks ok & might be fun in it's own right. I just wonder if the level design is sort-of dumbed down with all this "arena" type, fast-paced shooting becoming popular. What I really miss in games is great level designs with a unique look to each level designed around weapon placement & "flow" to the gameplay. Most shooters today have no flow to the maps, it's just everybody everywhere for the ADHD crowd that needs constant action. One of my favorite games of all-time was Halo 2 because the maps were so good. Headlong, Terminal, Zanzibar, etc. all had smart layouts with gameplay designed around the flow of fighting over the power weapons. I feel like a lot of the games today just start copying each other then they are very similar over all. There's hardly anything to distinguish themselves as their own brand anymore. I still don't see why Halo can't focus on being Halo & what made it popular in the first place with updates to keep with the time obviously as well.
What leads you to believe that is the case here? If anything, the move-sets are increased in complexity and options. This adds room for nuance. The number of shots to take down a spartan alone will drive away your "ADHD" COD crowd. I'm encouraged by the de-emphasis on load-outs and the bazillion slight weapon variations that bog down COD and Battlefield and make balance nigh-impossible, as well as the gameplay enhancements actually revolve around movement and attack options that everyone has access to all the time.
Among the 3 maps they have shown are a Halo 2 remake (Midship), and a mini version of Hang-em High (essentially). There will be Seven maps in the Beta, so they have plenty of opportunity show off some bigger maps. I really doubt they will all be small arena maps.