The adjective, which I assumed was being used in the Brittish sense, is one that says to me that while they may have tried a Proc bombing build, they didn't try a well designed one.
Proper in the American sense would be more like the "this is the correct way to build"
The implications are more relevant to game design. It says the Homecoming effort to rebalance procs is too little, too late and that, like SS rage, this is the way things will remain.
Which suggests the two variations on the term Proper will merge in the future. Evidenced by the post where I am called a clueless forums dweller. And of course the one where I need the forums cartel to come and save me. And so SMDH.