I found a really interesting interview with the British actor who played the blond bad guy Hallenger in a few episodes. Here’s some comments he made after the show got cancelled: http://www.digitalspy.ca/british-tv/s56/flashforward/tubetalk/a316491/qa-a-chat-with-neil-jackson.html --
We've got to talk about FlashForward -lots of people were upset when
that was canceled. How did you feel?
"I was pretty upset. I had a long chat with [David Goyer, the creator
of the show], as we were coming to the end, talking about who was my
character and what was he about. They were very cloak and dagger at
the beginning about giving me information -they couldn't tell me who
he was or where he came from. I wasn't allowed any backstory on the
character, which was difficult, trying to create the character when
you know nothing about them.”
“But the plan for the second season was we find out the reason that
my character had been causing these blackouts was to cull large
numbers of the population, because he'd had so many FlashForwards
himself he'd ended up seeing the future. The world within the next 250
years, looking at all the statistics, is going to become way too
overpopulated for our natural resources. Famine, pestilence, drought
-all these things will become commonplace. So as a humanitarian he
wanted to indiscriminately kill lots of members of the population to
try to bring the human population down. He was actually in his own
warped way a good guy for humanity, which was a fascinating way to go
with the second season and would have made my character one of the
main characters and would be a really interesting, nefarious story.
But it didn't happen, unfortunately!"