From all docks I have tested, SliderDock was the only one that suits my professional needs more or less, and I've tested many of them. Please note that I'm not nagging about - I'm trying to get the best I've found improved further.
Causes problems? Possibly, yes. Depends on how one uses SliderDock. As an optional feature (or even a per-ring option, or on a hotkey, …) it won't bother those who use rings crowded to the extreme.
People in forums still keep complaining about Windows 7, because there's not decent way of organizing the most used documents anymore. On Windows XP one could arrange the icon in any folder freely like snippets on a desk. SliderDock will be an attractive solution to everyone who needs to work with documents effeciently, once an 'always show tooltips' option is available.
Please take a look at the overlay picture on mediafire.com in the folder /i/?3sts938f94jow0x
The mouse cursor has always entered the the icon from the top right. Looks tidy to me.