Just found this amazing Reddit comment which I wanted to share:
"Let’s go over the issue from the beginning.
First, it’s usually thought that the current Indian civ, aside from easily replaced flavor like leader list & wonder, with its camel & gunpowder focus, is entirely based around states created by Islamic conquest, i.e. Delhi Sultanate, Mughal Empire, and everything in-between.
The Prithviraj campaign, on the other hand, has the player control a Rajput kingdom that resisted said conquest. To reflect that, during the campaign the player can’t even research the UT “Sultans”.
To rectify the situation, the community’s two commonly suggested top priorities are to add a Bengal civ and a Dravidian civ, the later usually called “Tamils”, to represent the very distinct cultures and military traditions of northeastern and southern South Asia.
Next to them, the 3rd place suggestion is usually either a Gujarat/Rajput civ for the northwest, or another Dravidian civ, usually the Kannada people (Kannadigaru).
And now we have a possible leak of the new South Asian civs posted on this subreddit. The leak shows us models of UUs that are consistent with official teasers, which cannot be easily faked. So either the leak is 100% real, or its author had access to real portraits of new UUs. The leak shows a pattern similar to the suggestions:
** The Elephant Archer becomes a shared regional unit. This seems pretty much confirmed by the “unupgraded” Elephant Archer in the teaser.*
** The original Indian civ is renamed Hindustanis.*
** A Bengali civ and a Dravidian civ are added, though as been criticized, the latter seems to be another awkward umbrella that has to try to cover all four South Dravidian cultures: Tamil, Telugu, Malayalam (Kerala), Kannada (Tarnataka).*
** The third addition is the Gurjaras, apparently using the word as a broadest general term for northwestern India including the Gujarati and Rajputs.*
If the leaked scheme can be trusted, they’d probably have to change the player civ in the Prithviraj campaign to the Gurjaras (or whatever the northwestern civ is called), for the sake of keeping civ identities straight. If they do that, I think all AoE2DE owners will have access to Gurjaras, while keeping their access to the original Indians/Hindustanis, raising the number of “basic” civs in DE to 36.
You would then buy the new DLC to access the 2 new civs of Bengalis and Dravidians, continuing the pattern of DE DLCs. The 3rd new campaign would be for the newly vacant Hindustani.
(Come to think of it, we may also see them do that to Dracula if the progress of adding popular civs ever moves onto the Vlachs/Romanians.)"
That would also explain why we can’t find a Gurjara nor a Hindustani screenshot. It simply doesn’t exist because Hindustani and Gurjara are going to be base game South Asian civs.