It's not as daunting as you fear. It just takes, like most things worth the effort, a little preparation. We've seen all sorts of wild origami folding tricks and not only is this the easiest, but it's the most effective. Think of your suitcase like a sandwich—your pants and jacket will be the bread, the filling is everything else (from sweaters and shoes to underwear and toiletries).
Fold the pant legs back into the case and lay the jacket on top of everything. (Do this right before leaving to minimize creases and wrinkles.)