In general procfs export kernel information of processess while sysfs export information about devices and other kernel objects.
However procfs also export kernel subsystem information not related to proceses, which make procfs procfs cluttered with lots of non-process information. These should be replaced by sysfs.
e.g.
root@gerrit01:/home/vagrant# ls /proc/ | egrep -v -E "[0-9]+" | more
acpi
buddyinfo
bus
cgroups
cmdline
consoles
cpuinfo
crypto
devices
diskstats
...
References