Firstly, (non-muslim) AI empires dont explode. They just used to blob out, Byzantium eating Sicily, the Balkans and anything east of them, the HRE stomping Flanders, Aquitaine and anything their border-dukes have claims on. It´s been years now that i´ve seen Byzantium collapse or the HRE disintegrate. It used to be like that when TOG or LOR came out, but that´s quite a while ago. Since then, (non-muslim) empires who get in trouble just get elective and stay stable until 1453.
Conclave/patch 2.5.2. arguably changed this. No matter how often critics like to post that it only "slows blobbing, but does not prevent it" it is simply not true. I havent seen Sicily being eaten entirely, or Aquitaine being swallowed by the HRE since then. The AI has become far more agressive leading to some weirdness in North Africa among other things, but the AI will usually refrain from wars when threat builds up, and this slowing comes to a grinding halt because at some point there just are too many powerful vassals.
It is irrelevant how much time the devs spent on coding this. Fact remains, that it´s basic premise to stop or limit snowballing works, and i´m still waiting for arguments against it that don´t just come down to "make blobbing easier". You say, it is an insult to players, but the question is why do you hit such high threat levels at all?