There is definitely usefulness in clean high ISO, it pratically gives you more light, which in turn create photo possibilities that was previously not possible. It's one of the more useful advancement then pixel count/live view, just to name a few (in my opinion).
Why is Canon sitting duck ? that question had been asked countless time and speculation/answer in this longest 'next model' thread in clubsnap. Well, my assessment is as follow:
Canon was threaten from the low end, which see a slew of low cost models from Olympus, Sony and Nikon that is eating up their market share. So, the focus had been shifted there, hence the slew of quite decent low end offerings from Canon recently (450D, 1000D). At the same time, Canon top-end 1 series had seen technical challenges from their quality issues as well as AF issues, sucking away significant resources to contain the problem, which till now still had not restore the confidence level of the pro. This is a big threat not mainly because revenue/margin from the top line is large, but rather there is a propagative effect from the perception on what Pro choose to use, in swinging mid/low end purchase decision. Just think of the rows and rows of big white lens on major sports event. In fact if you see, Canon had tried to up the high ISO game in the recent 1D mark3, up the ISO to 6400. And in typical of Canon approach, they normally quite conservative in pushing their ISO control in their DSLR compare to other brands. For example, D30/40 ISO 3200 is probably close to D200 ISO 1600 (which uses CCD sensors), but D200 boldly include 3200 in their D200, and Canon actual sensitivities is actually higher then what's claim (eg. ISO 3200 is closer to ISO4000), wherease Nikon ISO 3200 is closer to 3200. So 1D mark3 can comfortably manage ISO 12800, but still still lag behind D3/D700.
Nikon strategy in D3/D700 is quite smart, and in one sweep, they threaten Canon 1 series, and at the same time D700 foray into a new segment which was absent in Nikon, so there is nothing to loose from Nikon and everything to loose from Canon. Timing is also perfect when Canon is struggling with their 1 series issues.
Canon is definitely scrambling for a response now, but they are probably limited in their options. Their so call 5D2 is probably inferior to D700 (the usual market segmentation internally focus, they had monopolise for too long and they use the old assumptions on competitor line up, and D700 threw a curve ball and they were caught off guard). They can choose to push the 5D2 with lower price and lower spec then D700, but that will not goes down very well with their branding and positioning, too close to 40D as well, which is a sizable segment for them. They probably need more time to have a model that match or surpass D700, and worry also on impact to 1D value proporsition, and consumer patient is running low in waiting for the next model, as you can see from the length of this thread. On top of that, they also is also trying their best to speculate what is next from Sony in the similar segment, which will certainly have something very close to D700, and with image stablelizer built in, and it will be qutie embarassing to be upseted twice in a row.
Another big threat they are worrying about is the Nikon D3x, which is likely to be a 24MP FF D3. And likely something similar from Sony very soon as well. 1Ds is too new for upgrade, AF still a bugging issue. Would be interesting to see how they response. One possibility is to boost up on their Pro lens lineup, if they can offer some significant upgrade to their L lenses, they can still keep some of the switch, which was also why they push out the 200 f2, 800 f5.6 recently. So next up is probably 24-70 IS, 100 Macro IS ?
This is a major full frontal assult, and boy I am seriously enjoying this. Like watching a real life ancient art of war is display. I am sticking to Canon for now, but I'll enjoy this competition.
