Lincoln, in his time, was for more government intervention than the Democrats were. However, I think it would be unfair to call him a moderate or conservative Democrat in today's terms. The Democrats might have been more anti-government, but that doesn't make Lincoln a Democrat in today's terms. He knew the wisdom of limited government infringement upon the liberties of man.
I see your point. By today's term the interjection of the Feds into personal Liberties, Lincoln would qualify as a Libertarian. He use to get slammed in his political campaigns by the "Religious Right" of his day as an atheist. The problem is modern political terms do not really fit all that well to historic figures. While he was Libertarian in some aspects of his ideology he was almost a Socialist in others.