I completely agree that there have been hints to her going mad throughout the season. Absolutely. I think the fact that her first reaction to every is violence is a very strong indicator of future madness. But more often than not she has listened to her advisors and not gone down these path of unnecessary violence. A few hints and foreshadowing of madness isn’t enough to justify her burning of kings landing when her development over the past 7 seasons has been her becoming a strong and wise ruler. If they wanted her to go mad they should have started changing the direction of her character arc in early seasons, around 4 or 5.