Just for the record,as an example-India has never had an Aryan/Dravidian division. Someone with an overactive imagination and bucketloads of creativity set about creating this myth that has been the cause for so much turmoil in recent times. The vast majority of all Indians share a common genetic origin and are part of the same 'culture' group,with the only differences being geographic/linguistic in nature.
In game culture groups aren't only about ethnicity or language though (but they can of course be part of it). Otherwise you'd have one giant germanic northern european group in Europe.
The indian culture groups does help to promote an historical outcome. The early modern india certainly had a southern and northern sphere of action so to speak.
That said the indian setup in eu3 is ofcourse laughable in general. But the culture group I can atleast see the idea behind