Well Halo has jumped the shark folks. In a recent press release from Microsoft, Phil Spence states, "I think one Halo game every three years - which was kind of our old cadence - is probably not frequent enough."
I belive the above image is an accurate example as to what is going to happen to the Halo Universe. You can already see the franchise beginning to splinter; Halo: Reach was an abomination in terms of canon. With annual Halo Releases, the backstory will become further fragmented and the games will continue to decline. Declining gameplay will be accompanied by declining sales and ultimately the Halo series will be reduced to something akin to Metal Gear Solid or Zelda. It will have no real point and instead of being a standard bearer for Sci Fi story it will become a COD multiplayer, with a pointless story.
Every single Halo game has to one up the predecessor. For example Halo Reach had all the features of every single Halo game, but a sub-par campaign. The campaign was sub-par to Halo fans because it did not reference canonical books. Future Halo games will continue to decrease in quality because they will not reference the anime, books, and possibly even game plots. These games will however continue to add new weapons and vehicles that were never seen in the Halo games. These weapons and vehicles would have been used during the closing battles of the Human-Covenant War. The new 343 Industries Halo games will continue to enlarge plot holes by introducing new weapons and vehicles, possibly even new covenant races.
Essentially, what is clear, is that 343 industries (the company taking over the Halo line) is in this for the money. Bungie started the series, and for the first two games might have even cared about the plot, but as soon as they changed Halo 2's plot so there would be a cliffhanger sequel, they stopped caring. Halo 3 was a good Halo game, but Reach shows that Bungie has sold out. The new game studio 343 Industries, and their annual Halo games will further sell out the Halo series. What could have been a perfect, classic, Sci-Fi series was destroyed before it even got the chance to fly. 343 Industries will continue to sell out the Halo series, for the next 10 years, to get more and more money. They will fill Microsoft's coffers with annual Halo games. The one thing they don't understand is that gamers care about quality. We just don't like to shoot stuff, but we like story. By ruining the story that the game developers themselves establish, your selling out, and thus will lose loyal fans like myself.