After my first attempt at good homemade masala chai, I've made a few more attempts. My takeaways from the first time were less sugar and less cardamom.

Attempts

1. Less sugar, less cardamom, and less tea: I didn't want my masala chai to be a sweet drink, just enough sugar to bring out the spices. I felt the cardamom was too strong the first time, so I lessened it by a pod. I also moved to a single serving English Breakfast Tea instead of the family Publix tea. The first time the family size is all I had, but I felt it was overkill. The results of this attempt were decidedly less strong.
2. More cardamom: With the weaker second attempt, I decided to increase the cardamom back to the original 4 pods. I still felt this attempt was weaker than the first attempt.
3. Even more cardamom: I increased the cardamom by another pod, but didn't feel the increase was noticeable.
4. Cloves: I thought maybe the flavor was flat due to only using ginger and cardamom as the spices, so I added a couple of cloves. The flavor was still lacking compared to the first attempt.
5. More tea: Perhaps the missing flavor was due to the smaller tea bag. I used another family tea bag, but it still wasn't as good.
6. New ginger: Was my ginger getting old? I tried again with some freshly purchased fresh ginger, but the flavor still wasn't there.

At this point, the only aspect left that might affect the flavor is the sugar quantity. I didn't think that the sugar would affect the perceived spices this much, but I can't think of anything else that would be the difference. Perhaps, perhaps, I'm losing potency in my spices, but I can't imagine I'm losing so much flavor so quickly. Either it's the lack of sugar or the aging of my spices. I'm not interested in increasing the sugar. I want this drink to be available to me; I don't want to feel like it has to be an infrequent treat. If the spices truly are losing flavor this quickly, then I think I'll just have to resign myself to the fact that the flavor is subject to significant change from one brew to the next.

Next Steps

Given that I'm unwilling to increase the sugar, I'm left with trying to extract more flavor from the spices. I have two plans to try and achieve this:

1. More water and longer boil time: A longer boil should get more flavor out of the spices. More water will make up for the increased volume lost due to a longer boil. I'll start with 6 ounces (a 1.5 times increase) and boil it down to 4 ounces.
2. More water and more milk, all at the beginning, with a longer boil time: Perhaps putting all my liquid in at the beginning will help with extraction. I'll increase water and milk to 5 ounces each for a total of 10 ounces and boil down to 8 ounces. I'll then add my tea and steep.