Seems hardly fair to count handheld versions. And Halo has seen a new game released every fall for at least the past 3-4 years. The only thing bring its average down is the Xbox era, where it was 2-3 years between sequels. At this point it comes out almost as often as Call of Duty.
Why? It's fair to count Halo Wars (a completely different genre), Halo Anniversary (a budget remake), and Halo ODST (produced mostly as an expansion).
So then it's fair to count Uncharted: Golden Abyss, Resistance Retribution, God of War Collection, God of War: Chains of Olympus, God of War: Ghosts of Sparta. Why not?
They aren't small cash-in titles. They're legitimate full-fledged games in the exact same vein as their console counterpart with fairly high production values.
Four Uncharted games in 5 years.
Six God of War games in 7 years.
Four Resistance Games in 6 years.
The point is that when a Halo game is announced, it's very much in context. A 10 year Anniversary remake is NOT milking the damn franchise. Having Ensemble make Halo Wars with a completely different story in the universe based on the original Halo concept is NOT milking the franchise.
The one legitimate complaint I can see is that ODST was priced as a $60 release, which is a shame because it would've been a lot better received at $40, critically and commercially.
No one scoffs at the 10 Resident Evils or Zeldas or Mario in a single generation but people want to bundle each and everything Halo under one banner and claim its being milked. It's bullshit. Everyone understands what a mainline Zelda is. What a mainline Final Fantasy is. They need to do the same with Halo. The last main course Halo game came out in 2010, and before that in 2007. Everything else is an appetizer.