The problem is that it is really easy to move "profit" from one place to another. A common ploy is to have one part of a company that is in a low-tax area to charge other parts of the company "licensing fees". In some cases this "licensing fee" means that the other parts of the company now make no profits.
If you try to tax revenues rather than profits, then you wind up really hurting (true) low-margin companies, and wind up under-charging (relatively) high-margin ones.
The best proposal I have seen yet is to tax companies on a percentage of the global profits based on the percentage of revenue earned in that tax district. However this would be really difficult to enforce in a reasonable way because 1) How do you audit all of the books in all of the countries to make sure they are not just hiding things? 2) It is still difficult to define profits, especially when you have multiple countries laws to deal with. 3) There is a major possible loophole in just moving all of the profits from one company to another using the same "licensing fee" trick, and having the licensing company have a presence only in a tax haven country.