India is a subcontinent. The modern Republic of India recognizes 22 regional languages. It's wildly diverse.
It's also foreign, far enough away from most popular Points of Divergence, and remote from pop culture consciousness. Because authors are lazy (or overworked), a surprisingly common shortcut is to have India turn out pretty much like it did in reality: as a single unified state.
Like all too many National Tropes, this is simple, obvious and wrong. Historically, India's usually been as disunited as Europe, for the perfectly valid reason that it's as diverse as Europe; most of its provinces could function pretty well as sovereign nation-states in their own right. They may or may not have consolidated more than that left to their own devices, but OTL they weren't; the assumption that India's united (or could be united, for that matter) is due mostly to centuries of work on the part of the British East India Company.
Bland United India is a form of Space-Filling Empire (especially when it's a United India, incorporating OTL Pakistan and Bangladesh.) Usually, neither Bland United India or any of its citizens feature prominently in a work that includes them; when they do, That Other Tropes Wiki already has a page about how it's usually portrayed.
- GURPS has played with this trope several times in several ways.
- Played justifiably straight in Cornwallis; the age of imperialism never ended.
- Played dead straight in the Dixie timeline, including Pakistan and Bangladesh.
- Notably averted (along with many other things) in Aeolus. While France controls the Dravidian south and most of the shoreline, the Mahratta League controls what used to be the Mughal Empire, and Sikhs control the Punjab (and what looks like a fair chunk of Afghanistan too.)