As has been mentioned his time was explicitly called out as when good held sway.This is a misreading of the setting. It's not "too much good". You will not find that anywhere in the actual text of the setting. At no point does anyone claim that the Kingpriest was "too good" and thus had to be put down. The Kingpriest was too LAWFUL.
[Citation Needed]The problem is, people are equating that with "good vs evil". The setting IS NOT ABOUT GOOD VERSUS EVIL. Again, Takhisis is the Queen of CHAOS. Not evil.
There is a dispute by D&D's various creators whether Takhsis is actually Tiamat (who is Lawful Evil) but I can't track down any source material claiming that she's Chaotic. I don't have her statblock from Dragonlance - but if we look at the Dragonlance Wiki she's definitely Lawful Evil.
This "she's chaotic" fits precisely zero of the official source material I'm familiar with - and the 3.5 Dragonlance campaign book (by Weiss and Perrin with foreword by Hickman) explicitly talked in the opening section about how the setting was a "conflict of good and evil". Meanwhile the 2e Player's Guide to Dragonlance under The Gods of Evil on page 88 explicitly states that "Takhisis is the embodiment of Evil". Not chaos. Evil.
So I'm very curious to see if you can produce any information to back up your claims that Takhsis is the "Queen of CHAOS. Not evil." when the books themselves disagree with you. I agree that if you were to reorient Dragonlance as law vs chaos it might make a more cohesive setting - but that's not the setting we have.
And I forget who suggested that Dragonlance (DL1 Dragons of Despair came out in 1984) came out before the two-axis alignment chart in the 1979 AD&D DMG.