As it includes every Halo game prior to the release of Halo 5, remastered for Xbox One, Halo: The Master Chief Collection represents one of the biggest installs currently available on the console. And now with Xbox One X enhancements due next year, which is awesome news, we should expect to see this compendium cross the 100GB install size threshold. Which is okay when you consider it's more than one game.
Also developer 343 announced that alongside the update any remaining bugs or glitches would also be fixed. Which is nice cause everyone kind of remembers the rocky launch plagued by matchmaking issues, so it'd be great to see everything ironed out once and for all.