There goes another internal engine in favour of Unreal Engine
I'm a bit worried about switching engines, I hope it still "feels" like Halo and things like Forge are still possible.
Having said that, if Microsoft wasn't willing to staff up 343 further then ultimately an engine swap was inevitable and will likely be for the best.
As I said though, this is essentially a studio reboot, Pierre will rebuild almost a new team, anyone who didn't want 343i working on Halo anymore should be happy...This is 343i in name only at this rate, in fact I'd say they probably should change the name.