Why isn't Halo Reach on the survey? Because I wanted to pick that. Any Halo lore fan worth thewir salt would pick Reach. Allow me to release my Halo nerd trivia lol:
- Brutes and drones had no place during the invasion. This was because Drones are regulated to being the maintenance workers aboard Brute ships (because Prophets forbid them to have Huragok/Engineers) and because this takes place before the Great Schism. The Elites would do no such thing as let the Brutes share in the glory of a ground invasion alongside them. Their addition was to add in enemy variety but Bungie disregarded the canon in doing so. Source: Novel Contact Harvest
- Spartan 3's were supposed to be super top secret. As a even more ethical PR disaster then Spartan 2's were, these soldiers were bred by the hundreds, induced premature puberty, given rushed training, and sent on suicide missions. Their existence was only known to privileged members of ONI and high admiralty. They should have reported to ONI officers, namely Kurt, or Ackerson. Anyone else would violate their secrecy. This is especially wrong to include a S2 in their company....as S2's were public knowledge. S2's and S3's never met until after the events of Halo 3....until Reach contradicted this. This was likely to make the teams meeting with Halsey more impactful, but if Bungie took care of their lore, Jorge had no place with that company. Source: Novel Ghosts of Onyx.
- Covenant Supercarrier elaborate plot to destroy it. This plan to deliver a slipspace engine into the ship and set it off is inherently dangerous....and completely unnecessary. Reach is the human military capital among its colonies. It is said that dozens, if not ships numbering just over 100, orbit Reach at any given time. The game made it seem like Reach orbital fleets were non-existant and only had a few ships to spare. In reality, the Supercarrier, once exposed, would have been ganged up on by the MAC rounds of the fleet, as well as the orbital MAC cannons, within minutes. Source: Halo Fall of Reach novel
- Ships warping in, inside the orbit of the planet. After the supercarrier was destroyed, many Covenant ships just warp in, in orbit. This is a direct contradiction to the novel, where the fleet warped in far outside the kill radius of the orbital MAC cannons, and thus proceeded to charge them, destroy them, and then land parties. The ships warping behind the cannons also makes no cannon sense in that the ships didn't even know how to until after Halo 1 events. After Halo #4 blew up and Chief made his journey to Earth, a covenant AI recorded Cortana doing an in-orbit jump, something Covenant ships did not do before, presumably for convoluted religious reasons by the prophets. Only then did Covenant learn to slipspace jump inside a planets atmosphere....and behind any orbital defenses. Source: Halo Fall of Reach/Halo First Strike novels.
Then there's the minor complaint on how the Reach satellites, radar scanners, and AI's monitoring the planet let ANY covenant past their defenses at all, let alone set up any camp, cloaked or no cloak.
Oh....and how its multiplayer made things unbalanced and took away from the competitive aspect that Halo 2 and 3 strived to achieve.That too ;)