In case you want to see the spartans in all their glory, the mod to play with the third-person view in Halo: Reach on PC could be your solution.
The arrival of Halo: The Master Chief Collection and in particular of Halo: Reach on PC has paved the way for mods in the famous Bungie game, obviously in the PC version, as shown by this particular modification that allows you to play with a third-person view.
There is, therefore, a new mod that allows you to play Halo: Reach with a third-person view, but only for the Campaign at the moment, therefore not the multiplayer modes. On the other hand, the Halo series sporadically includes the transition to the third person with the use of detachable vehicles or turrets, so a graphical preset for such a shot is probably easier to find, digging into the code and building changes special.
This also determines certain effective usability of the third person in the Halo: Reach Campaign, given that it is not really an alien introduction to the game mechanics, although obviously this is not an advisable choice for the more technical players.
If you are interested, find the mod in question in the Nexus Mods portal. 343 Industries had already reported in the past that the mods would be supported at launch but not officially for Halo: Reach.