In some sense I agree with you. And it seems that, anyway, the big multinationals can find ways to squirrel away their profits without having to pay much, if any, taxes anyway. So in this way corporate taxes hit the SMB's while the big boys get a free pass..
However, one argument against lowering corporate taxes I've seen is that it would incentivize people to skirt around their personal taxes by "using" corporations. Instead of buying your own car, let a corporation (maybe your employer, maybe your own 1-person corporation that everybody would set up in a system like this?) own the car and you just use it. So somehow you'd need to prevent that kind of behavior. Perhaps shifting the tax burden from income to consumption would do that, IDK and I'm too tired to think about it now.
Another tax that economists generally seem to think well of, is land value taxes (originally by Henry George, IIRC). But these seem more or less impossible politically, as the politicians are generally better of than the average Joe and tend to own more land/property..