Well, I'm not really against corporations per se. I work for one I quite enjoy and whose aims I think are good and in the general interest.
The challenge, as I see it, is to have governments with a spine, but governments not so big that they stifle freedom or crowd out opportunities. Governments need to be powerful enough to overrule the biggest corporations so that corporations can exist without the cronyism. Power alone is insufficient though because even a powerful government is peopled by individuals who can sometimes be bought cheaply.
The East India Company is a somewhat terrifying example of what is possible with unbound power for corporations. It's an equally bad and unsubtle endpoint as an all government central economy. Diversity of thought and composition, as in many places, yields better results than homogeneity.
I think corporations are necessary for large-scale, long-term commercial endeavours. Certain classes of services to both individuals and businesses need continuity and corporations are well-suited to providing that kind of continuity.
Where we are today forgives incumbent large corporations too much and (certainly in Canada) makes it far too difficult for entrepreneurs to start small businesses.