The install size for Halo Wars 2 on Xbox One X has been revealed coming in at a large size with the enhanced option being available starting November 3, 2017 taking up a total of 43.7 GB on the Xbox Marketplace. The base model/Windows 10 size is noted at 48.2 GB prior to the update. It looks as though compression or the new dynamic content download was at play to increase the size (the update) while decreasing the overall space on the console. The install size was grabbed from the console with the game having been given a decent update and it now showing up under "Xbox One X Enhanced Games" tab. The option to turn on 4k assets for games is present under "Settings - System - Backup & transfer - download 4k game content". This install size should be close to the final number as all the announced DLC has finished releasing though smaller updates may still come by to fix or tweak things.
Halo Wars 2 is an awesome RTS sequel that provides a Xbox Play Anywhere experience that includes cross-play. It continues the events of the first game with gorgeous Blur cutscenes and we see The Spirit of Fire return. There's a new enemy called the Banished and the Awakening the Nightmare DLC brings back the Flood. The entire game is presented at 4k (3840x2160) on Xbox One X with added HDR support. The product of these changes provides a deeper level of detail for the various troops and small blast particles that really pop with vibrant color.