I think they're really talking about different kind of artifacts. I can imagine that data dropouts could cause some strange artifacts similar to damaged transport stream packets received by a DVB receiver or something like that. The mud we're experiencing in the GH1 is hardly caused by data loss due to slow transfer rates (we're talking about 17mbps here). That's pure codec performance working at hardware limits either due to processing power and/or available memory. Remember that the Venus HD engine used in the GH1 is originally for image processing and not for video encoding. If it had a dedicated DSP for video encoding (e.g. like the HMC) it would be a different story.Yet that's exactly what the Canon engineers said was happening in the 5D Mark II. They specifically recommended to use only UDMA cards because using slower non-UDMA cards, occasional artifacts would crop up.
Still I totally agree with your previous posts. You buy a product for what it is, not for what it might become in the future due to some software upgrade. That's foolish. It's like buying a flat panel and expecting the vendor to upgrade the number of total pixels by a software update or something like that => Not possible at all.