Having just finished reading the Hide Glue book, I would hasten to say your strength observations are "scientifically" suspect.
Hide Glue does bond with wood in a different fashion than a PVA glue, such that it will work well when the wood has some "tooth". Much like the way plaster and lathe work. Hide glue does something called "adhesion" or, it bonds to itself. Which is why a toothed surface and hide glue work so well for veneering.
PVA glues do not have good adhesive properties (but do excel at cohesion). The more gaps between surfaces, the less wood to glue to wood bond you are actually making. (This is all based on what I think I learned, not from my homemade electron microscope......)
In my cartoon based mind, I see pva glue like a double sided carpet tape whereas hide glue is like stepping on someones discarded, warmed in the hot sun chewing gum with your deep tread hiking boots.
Maybe its worth further discussion as to why your jointer isn't giving you a good finished edge?
Jim