I'd say black pepper is essential - it gives a little bite at the back of the mouth that complements the ginger (also essential! :) ) perfectly. You only want two or three peppercorns though. Star anise is a great occasional addition, but I wouldn't want it every time.

Wholeheartedly agree. Black pepper is a seemingly strange, but necessary addition. It fills a small gap in the flavor profile between the tea and the spices. My preferred ingredients are cardamom, cinnamon, black peppercorns, cloves, and a very small amount of nutmeg. I like to add 1 part honey for every 2 parts sugar.

It's tough to get the perfect ingredient ratio without making large batches or using a scale.

Whole milk (or cream) is important for the fat content.

In general my chai does not come out as dark as the chai I had in the Pune region, but does have a remarkably similar taste. As I understand it they sometimes make the base the day before. The color difference could be because of my preparation haste, shorter brew time, different ingredients, or adding too much milk/cream.

The chai in India also has a different mouthfeel. I'm not sure if it's loose spices in the brew or if they add something but it feels almost like pulverized rice in the tea.