I watched the stream and to be honest it looks really fun. They seemed to striving for a balance with implementing their own elements while keeping to the fans expectations. Gone are armour abilities, and replaced with new ways to move around with the jump packs and unlimited sprint available to everyone at all times. Every other major shooter from Titanfall, Adavanced Warfare, and Destiny all included jumps packs to add more verticality, and Halo following suit is not really a bad thing, hell they had it before all the other ones did.
All weapons now have the basic zoom function and their is no penalty to movement. Not to mention that you descope again when getting shot so if you're trying to use the zoom to get the perfect shot there is some penalty if you are shot back at. I think Sprint being tied to shield movement is a interesting feature.
Now the features I am little weirded out by is the charging, sliding and ground pound. They add peculiar new elements and I have no idea how they will change the current gameplay.
343 wants to make their own Halo and Guardians looks to be doing just that.
I am excited but my optimism right now could change when we get access to the beta at the tail end of this year. Let's just hope its not another Halo 4 (which I did like, but as others I did not play it for very long).