I see where you're coming from, but I think your thoughts need to be taken just a little further. It's not that conservatives (me being one, for full disclosure) inherently favor corporations. It's that we generally feel that free enterprise is a good thing and that when corporations are allowed to thrive, they create wealth which creates jobs which, in turn, makes life better for the individual (and obviously for the higher-ups in the corporations, probably to a much higher degree). That's an over-simplification, and it's not utopian, but I personally believe free enterprise is the best foundation. I don't believe in propping up corporations for their own sake, just in giving businesses the freedom to operate, unburdened from needless regulation and taxation (note that I didn't say *no* regulation or taxation), for our sake as well as theirs.
On the other hand, it's not that liberals inherently favor the government. It's that they tend to believe that the government is the primary tool that makes things better for the individual, by restraining the Monopoly guy from getting rich off his/her exploitation, by promoting justice, and by evening the playing field between the little guy and the powerful business entities (i.e. via promotion of things like labor unions and heavy regulation). The problem that I see with that philosophy is that it makes the government bigger, more suffocating, and definitely more menacing than the big businesses for which they have general disdain.
Like you, I hated the Kelo decision, but I actually agreed with the Citizens United decision. The reasoning is that things like corporations and other organizations are simply groups of people who come together for a common purpose. That purpose might be to make profit, or it might be to further some social or political agenda. Corporations and organizations don't exist for their own benefit. They exist for the benefit of the individuals of that have a stake in them. And as such, I believe it is not constitutional to squelch the voices of these individuals, just because they've come together in a group in an organized fashion, and because they tend to have more money, and thus a louder voice.
I know it kind of feels wrong, but it's not much different from 10,000 people picketing outside of some building. They come together for some unified purpose to amplify their individual voices into one large one (sort of). We rightfully recognize that peaceful assembly as a right of that group because it's a right of each individual. So, the same hold true for people that are even more organized and who focus their voice in a different direction. That holds true be it for the NRA or Citizens United, or for labor unions, or for Exxon, or for any other groups like that.
I'm not saying there aren't improvements that can/should be made in how these entities communicate their desires to our elected officials and how our elected officials act upon that pressure. But we have to be very careful about letting them have their voice because that one collective voice is really the voice of many individuals, which is protected by the First Amendment.