We have been seeing the same iMac for so many years that we are now shocked to see a redesign, even though we have been waiting for it for years.
I liked it live, I saw it in blue. The bezels and the light blue gives "relax" when looking at it. It does not seem to me, a priori something negative.
I think the colors give people the possibility to match their desktop to their personality, as you do with the iPhone or the iPad (Air). Apple is differentiating the "consumer" and "professional" ranges and design is one of the main elements.
Years ago, Apple was giving color to their equipment, with gold, rose gold, approaching a different audience. With the Xr was the first approach to the colors that we are seeing today in many more Apple devices.
It is true that perhaps a more discreet or "less colorful" option is missing, such as silver with black frames or space gray with a black frame. But that will be reserved for the "Pro" or larger, more serious versions, more focused on the "professional" public. But I think the silver is a good choice for those people who do not want color, even if the frame is white, I do not think it will bother, since it is a product for the "home".
I don't think it's not business oriented either. Wouldn't a yellow or blue iMac fit in a store where yellow is the predominant color, or would a blue iMac not fit in an office with a blue corporate color? I do think it would look great.
I think the work Apple is going to do with Macs is going to be very important, and they are going to sell more than ever, because not only your Watch or your iPhone has to show how you are, your home also shows how you are, why not the computer you have in your living room, office, or kitchen?
The new color MacBook Air, with white bezels, will sell even more.
The MacBook Pro, large iMac or "Pro" and Mac Mini "Pro and Mac Pro will have more serious, neutral colors, for those who need more power and/or "sober equipment".