This is nothing more than desperation to reel in CoD fans. It's been illustrated why ADS don't work in Halo, this isn't a twitch shooter, the kill times are longer and with jumping, strafing and Halo's overall movement a player is just going to move out of your LOS and render ADS pointless/impairing. The only way to alleviate this would be vastly altering Halo to play more like a twitch shooter. Do we really want to see more stagnation in this genre, Remember that picture of CoD Battlefield and Killzone side by side and it's basically identical? That's no less a problem today since that was created. Halo actually felt unique among the sea of LT+RT game play that the FPS genre has been limited to, now it's going to lose it's identity.
I'll gladly stick with the MCC if this remains the case, hopefully 343 will get feedback that we don't want ADS in Halo and it'll be changed. That's what an actual beta next month is for after all.