Why are Champion spawn rates and remnant drops so inconsistent?

HE Carnival chain - lots of champions and lots of chests throughout. I counted 9 chests in Small Problem alone. (Yes it is high every time I run it)
HE Litany - plenty of Champions but almost no remnants and no chests. That is until you get past dragon then champions spawn like crazy and there are are sometimes 10 chests (High Priest wing).
HE Web of Chaos chain: moderate number of champions and NO remnants or chests in LOD, Servants, and Spinner.
HE Delerium, Acid Wit, Missing, Fear Factory - not many champions and max 2 remnant coins total in each.
HE Gianthold - Moderate number of Champions, a few remnants or chest in quests.
HE Sands - Moderate number of Champions, a few remnants or chest in quests, if any.

Plus some champions seem to be hardly any stronger than normal mobs (Like in GH and Carnival) but other Champions hit like a ton of bricks (Attack on Stormreach)

I pulled like 38 remnants from 1 chest somewhere, and other times I get like 1 remnant.