Upload & Sell: Off
A different raw converter is not really going to gain a lot. The issue is rooted in the hardware. The main improvement that Sony came up with in the Exmor sensor is in the analag-to-digital converter which mitigates fixed pattern noise. The technology is patented, and so that is why we still have FPN in Canon sensors.
It does, the tool (and how you use it) makes a substantial difference. Because some are better at dealing with that type of noise than others. The same is true of technique. People can reason away a lot, as in "this can't be" or "it doesn't matter much". In reality, it can; if you take advantage of it, it does. What really matters isn't the argument (or how well you can argue it), but that you can produce that photo when the time comes.
I also don't know that patents or IP law affects much in reality, it rarely actually decides much in the large scheme of things. While this type of litigation is very expensive, the courts are generally impotent or too slow and act too late to make a substantial difference. We are now dealing with a worldwide marketplace and worldwide product. Apple <-> Samsung is a textbook example of this. In the big picture, all that litigation didn't really change much at all. The reality is like it almost always is, with cars, smartphones, whatever -- a lot of companies own a lot of the different IP that goes into or around the sensor, and an equilibrium of cross-licensing, mutually established interest ("I won't sue you if you don't sue me") ends up being the way that most companies play that game. Everyone once in a while, someone breaks from this mold, Apple, Rambus, whoever. But the court case doesn't change much in the big picture, in the end they pretty much back where they started, except for having enriched some law firms and lawyers. That's why I don't buy the 'this is patented' argument at all.
As long as Canon is pursuing or addressing the problem, it can be fixed, in time. The only way it won't be fixed is if they simply don't care, or they care, but are incompetent.
Also, even if you play by the rules one hundred percent, IP can often be a detriment to development because it pigeonholes you into one way of thought or one way of dealing with the problem.