I don't know if developpers have wide screens, but users mostly don't :-)
So, I use panel options for hiding / showing it (like Hide automatically, Windows can recover, ...). But panel allways show too fast for me: 
whenever the mouse is on the bottom (or the side, for vertical panels) of a full screen  window, the panel is shown. It is very irritating when all you want is scroll down or resizing the window.  
Similarly panel disappear very fast if I move the mouse a bit out of it. This was the same with Kicker in KDE 1, 2 and 3 ad I should have report this sooner, but...

I don't like to compare with other OS, but have a look at the MacOSX dock: there is a short delay to prevent the dock to be display when the mouse cursor is near the edge of the screen.

Please add a configurable delay to show/hide the panel.

Reproducible: Always