I'm going to go out on a limb here and say that it is stale.

Stale because we've had a Halo FPS released every year since 2009.

Sure, one of those was Anniversary, so maybe slightly different circumstances... but then again, what was essentially replaying the same game as the last decade with what was quite literally a new coat of paint isn't exactly making it feel new or fresh.

The Halo formula is being burnt out, as are the people playing it, by short turnaround times.

Let's put this in context. Since the Halo franchise began back in 2001, there have been 6 main series FPS games.
In that same time frame, Nintendo have only released 3 main series Legend of Zelda games.
There was a whole 5 years between Twilight Princess and Skyward Sword, and we're talking about Nintendo's jewel in the crown, flagship series.
With Twilight Princess actually being a Gamecube game that was given a very basic port as a Wii launch title, the reality is that the Nintendo Wii only had a single true Zelda release in the consoles lifespan.

That's quite a difference.

Speaking of which, I've recently been alternating between Metal Gear Rising and Twilight Princess.
Having been unceremoniously and laughably whooped in my first attempt at case R-00 on Very Hard, I should get back to TP.
Right now.