I am not in favor of having a lower rate, for corporations, than for individuals .. but, I ain't the sharpest machete in the shed .... I do realize that our effective corporate rate, currently, is the world's highest. Japan does have one rate, higher than ours. However, for the past decade .. this is hearsay, so it may or may not be true ... for the past decade ... no Japan corporation has fallen into that bracket. That is why pundits always say, "effective".
So, from a point of competition ... it's what might need to be done to bring back US competitiveness, viz-a-viz business.
My stance against a different rate for corporations v individuals, is simply that .. if corporations are a "person" under tax code and an individual is a "person" IRC ... why should one group of persons be given special dispensation over another group of persons?
As far as many SubS and LLCs ...it ain't no big shake to be move to a C-Corp. The only difference would be the difference on retained earnings. Let's say you own several properties. You take far more in than you have allocated for living. If you have not pulled out the money ... it stays within the corporation and would be taxed at a significantly lower basis.
Beyond that, I see no benefit to small business. John's company makes widgets. After fully expensing his widget operation, John's company makes a million dolllars. All John needs for his lifestyle is the same seventy thousand that he's been living on ... he wants to have this extra capital for future expansion or just for cash reserves. John leaves the 930,000 dollars within the corporation and it is taxed and a significantly lower level.
I guess that's a good thing. It's just why should one group of "persons" be highly favored over another group of "persons", under IRC?