You make a good point about making a slippery version of some knots. I fact, you can make a "slipped" or "slippery" version of just about any knot where you put the end of the line through -- just fold the end and put the resulting bight through instead. Makes untying the knot a *lot* easier.
For example, take the common shoe knot -- when you think about it, the common shoe knot is a double-slipped square knot (or else a double-slipped granny knot, which does not hold so well).
I like sheet bend style knots in general -- i.e. an intersecting bight and loop. They are secure and their slipped versions are easy to untie. For example, I rarely use a square knot -- I much prefer a slipped sheet bend. The sheet bend also works with different size cords (make the thicker be the bight) -- while a square knot will not work at all if there is much size difference in the cords (the square not will just capsize).
As to the trucker's hitch -- I know that it is usually drawn, as the article did, ending with some form of half hitch(es) or slippery half hitch. Personally I strongly prefer to take the slip knot loop as the bight of a sheet bend, and tie it off as a slipped sheet bend -- I believe that to be a stronger and more secure way to tie it, while being at least as easy to untie.
Tautline hitches -- I have been meaning to bring that up for some time -- why ever tie a tautline hitch? Instead, use a slipped trucker's hitch. True, it needs to be retied to adjust, however once tied it will not slip (unlike a tautline hitch)it is trivial to until (also unlike a tautline hitch, in some conditions), and it is easy to make it as tight as you like. I even prefer the slipped trucker's hitch to having mechanical line tightening gadgets.