An option to list implicitly installed orphans would be a handy feature. Like the following script does (besides the explicitily installed orphans):

#! /bin/bash


allpkgs=`pacman -Q | cut -d' ' -f1`
for i in $allpkgs; do
reqs=`pacman -Qi $i | grep "Required By" | cut -d: -f2`
if [ "$reqs" = " None" ]; then
echo -n "[$i] not required"
inst=`pacman -Qi $i | grep "Reason:" | cut -d: -f3`
if [ "$inst" != " explicitly installed" ]; then
echo -n " - implicitly installed"
fi
echo ""
fi
done