Fair comment. Like many projects, Tk gets better with age. I have always basically hated every single interface I have ever used that is implemented in Tk (e.g., Gitk) but who knows, maybe it got better recently. I picked tkdesk as a representative example. Installed it, did a file open, and saw that much of what I'd expect to be present in a modern file dialog is actually there. And the mouse and keyboard interaction is basically OK and what you would expect. The icons less than pretty and lack text labels, a failing I have long associated with Tk. Theming is just the basic ugly Tk look. Then things started going south, Tk toolbar icons started painting themselves on top of my other windows. I closed the main tkdesk but the toolbar refused to go away. I right click on the topmost toolbar icon, which has no label, I just guess there could be some forward progress there and a menu pops up... *under* the toolbar. I go back to my browser to continue this report and the toolbar icons are now overlaid on top of my text entry window, and now right clicking on the toolbar has no apparent effect.
Basically, a bucket of bugs. This is exactly the sort of mess I have come to associate with a program that grew beyond the ability of the underlying framework to structure it. So I stand by my initial overly curt characterization of Tk. IMHO, the only practical cure is to migrate to a better structured language.
By the way, I'm still trying to figure out how to get rid of tkdesk and its phantom icons. Xkill didn't work. Time to kill -9.