#3 is allowed by DCM. Besides #2 and #6, all of those other features could probably be layered onto DCM with FastScripts (free for up to 10 global hotkeys, http://www.red-sweater.com/fastscripts/) and some trivial little AppleScripts, certainly nothing that couldn't be done in half an hour by anybody reading this site.
I think $5.50 is overkill for a system utility with some trivial extra shortcuts and visual enhancements.
EDIT: re #3, you can change the magnification of the loupe, not its literal size on the screen.
$5.50 is the price of 2 coffees, or one beer. If you use it all the time, a simple app is certainly worth that kind of money. If you dump it in a drawer somewhere to collect dust, maybe not.
By the size of the loupe I meant the size of the loupe, not the size of the aperture used to grab the colors. That's one thing DCM can do that CS can't.
As for the others, #2 is probably the most important of all for me, and would be hard to hack on top.
Even if it were possible, my time is worth more than $10 an hour, so I'll spend $5 to avoid a half hour of work hacking together some Applescripts.
It's only "wasted" time if you didn't learn anything while hacking it together, didn't have any fun, and gained nothing in redesigning it your way. But, to each his own...
Re: the loupe, yeah not sure exactly what you meant, but you can also change the magnification in DCM prefs.
You can set a global shortcut for anything with a number of apps, including the free and excellent (but more or less abandonware at this point) Quicksilver.
Sadly, custom triggers seem to not work in Quicksilver on Snow Leopard. One can create a shortcut hotkey and check some options, but the UI fails when one tries to define the Action.
I think $5.50 is overkill for a system utility with some trivial extra shortcuts and visual enhancements.
EDIT: re #3, you can change the magnification of the loupe, not its literal size on the screen.