As for the 6:3 ratio, I'm becoming increasingly convinced the DLC character will be a woman, and since I rarely play as a male character, for me it'll seem more 6:5/6:4. Throw in a bunch of major female characters like Celene and Morrigan, and I really won't notice to be honest.
Yeah, this is a good point. You could end up with the same kind of ratio with a male mage Hawke. There would be 6 guys (Hawke, Carver, Varric, Anders, Fenris, and Sebastian) and only 3 ladies (Aveline, Merrill, and Isabela).
But if you played as a female warrior/rogue Hawke, it would be 4 guys (Varric, Anders, Fenris, and Sebastian) and 5 ladies (Hawke, Bethany, Aveline, Merrill, and Isabela). Hawke's gender and class really affected the ratio in DA 2.
That makes me wonder if we will have a Carver/Bethany style character that is affected by your gender and/or class. Or even a Kaidan/Ashley style character where a plot point you encounter causes you have to pick one or the other. Since we are missing confirmation on a third of companions, there's plenty of room for this type of character to be in the game.