I don't think its an issue on 50D+ at all. Just don't shoot things with moire in them.
1% I have the greatest admiration for you as a developer, but I find this advice not so expert. First, moire is, foremost, a psychological reaction to visual cues. Our brains are wired to move about our environment and abstract a physical reality in which we can move, make sense of. Is that a Jaguar in the shadows? Is this a puddle, or the edge of a canyon wall? When our brain is confused by what it thinks is a line that should connect, we see moire. In short, moire is our brains way of saying 'this doesn't make sense, look harder, or watch out, I don't know what this is!' So moire is a HUGE problem in video because it distracts the viewer from the general image.
Moire is a both a naturally occurring phenomenon and a description of similar aberrations in digital images. It can be produced "technically" by the camera creating artifacts between disconnected pixels (visual information).
Yes, I don't want to shoot things that are known to produce moire. But I have two practical problems. One, I can't see if moire has occurred on the LCD of the 50D. I won't know until I'm off the set and looking on a monitor. If it's there, getting rid of it is not easy. Yes, the effect can be mitigated by choosing better debayering, but NOT eliminated. Second, sometimes I want to shoot a house, say, and I can't do it in non-crop mode without getting a lot of distracting moire/aliasing effects on the siding, say.
Please don't think I disagree with you on how the 5D3 has solved these problems. I do not know. It might be a filter. It might be binning. All I was saying is you were implying it is a filter and not being clear that it is your opinion, not fact. As a very well respected dev your opinions means a lot on these forums. With 'power comes responsibility'

I hope we can both work together to figure it out and find solutions in the meantime.