Just keep in mind that Halo 5 was stated to have been started on well before Halo 4 launched, so the actual release cycle is probably closer to two and a half years. I understand concerns that this new Halo might be rushed, but if the trailer is indeed for Halo 5 it will have almost as long a development cycle as Halo 4 did.
Like I said, I understand your concerns, but Halo 5 was not begun immediately after Halo 4 was released 
it might be less rushed than we think.
Thanks.
-Dargons