Product development is an extremely expensive process which involves much more than just cramming all of the desired features and functions into a box and slapping a price sticker on it. I'm sure you can name at least one brand which seems to do just that and completely neglects style and usability. In the automotive industry, the red tape required for bringing a new car chassis to the market is prohibitively long for some would-be start-up manufacturers. There are a lot more supercar companies than just the big names of Ferarri and Lamborghini. Each year a supercar will hit the market, but the development and production costs are just too great to be recouped by sales and the company will file for bankruptcy. Even the long established companies prefer just tweaking previous models, and in the last five years only a handful of completely new car chassis have hit the market worldwide.
While computer part companies aren't as likely to be susceptible to the same fiscal hazards as a fledgling automotive company, the same design practices makes a lot of sense. Why spend the resources on developing a completely new design if your existing model line just needs to adopt some improvements? Not only that, but we gamers have our loyalties and like to stick with certain brands and sometimes we just want to have the latest features in a familiar product. Cooler Master's original 690 is still amazing when compared to a generic mid-tower, but it just won't sell to those gamers who want to take advantage of features like water cooling, good cable management, and USB 3.0. The 690 II included newer features such as eSata, support for large aftermarket CPU coolers, and 240mm radiators, but even that has now gotten to the point of being insufficient for the latest in gaming technologies.
Cooler Master's 690 III with Seidon 120V cooler (CMS-693-KWN1) is the third generation of the 690 series of cases. Much of its design comes straight from the 690 II and has been revised to fulfill more modern demands. Improvements include modular hard drive cages, large video cards up to 423mm, three dedicated SSD mounting points, and support for two 240mm radiators. If you get the version without the side window (CMS-693-KKN1), you'll also have support for a third massive 200mm fan on the side panel! The front I/O panel has gained a larger cubbyhole and ditched the mark II's eSata port in favor of the faster and infinitely more useful USB 3.0. The opening on the motherboard tray for custom CPU cooler mounting is also larger, and cable management is improved by rounding the edges of the motherboard tray pass throughs instead of rubber grommets. If you want to add a fan controller, there's even an offset expansion slot on the back that won't interfere with add-on cards. And let's not forget that this one comes with an All-In-One water cooler. I think it would be easier to have listed what features the 690 III doesn't have.