For conspiracy theories regarding moves in the comic book industry to really truly exist, there must be some precedent for said moves.
The ending of the Armageddon 2001 mini-series is an example on which all future conspiracy theories rest.
In 1991, DC had a summer crossover among all their annuals. A man from a future ruled by a despotic former superhero named Monarch travelled from 2001 to 1991, to discover what former hero became Monarch.
This man, Waverider, had the power to see people's futures upon making physical contact with them.
Each of the annuals that year he would check out the future of those characters, so each annual would be a story of the future.
In any event, DC had it planned to be Captain Atom to be revealed as Monarch. However, news of this event had leaked well before it was revealed (or, as one other rumor goes, the folks who licensed Captain Atom to DC were not pleased with DC making him a big villain - but that is unlikely to be the real reason, as people on the "inside" all refer to the incident as "the news was leaked, so we had to change it quickly").
Hawk, from Hawk & Dove, ended up being the sacrificial lamb.
Here is Barbara Kesel, writer of Hawk & Dove, on the topic (courtesy of the great resource Titans Tower):
Let's get one thing clear: that wasn't a planned ending of Hawk and Dove. That awful story was an Armageddon 2000 special created after somebody at DC spilled the beans about Captain Atom's being Monarch. Then, a small number of people worked feverishly to find some other character to sacrifice, and since H&D had just been cancelled! "
If you've ever pitied anyone, pity Jonathan Peterson, the poor person who had to give me the news. I wasn't pleased, and wasn't shy about sharing. If there's anything I hate with a passion, it's characters behaving out of character, especially when it involves a smart woman being stupid for no reason. H&D becoming Monarch could have been a clever idea: if they BOTH became the character, their innately opposite natures could explain a schizophrenic villain. As it was... it was a last-minute fix that sucked.