The only impressive feat Hanzo had ever shown was beating the Sanin before they were at their strongest.
-Jiraiya lacked Sage Mode and Rasengan
-Tsunade didn't have Yin Seal
-Orochimaru lacked regeneration and Edo Tensei plus he commented that he was weaker than Early part 2 Sasuke when he around his age, meaning Jiraiya and Tsunade were at around the same level.
On top of that, we don't know what other abilities they had at the time or if their summons were used at all. The most we can assume is that they were basically around the same level as team Yamato during early part 2, which any low kage level shinobi could probably solo. Jiraiya was shocked that anyone alive could beat Hanzo but keep in mind this: Minato, Hiruzen, and Orochimaru were all dead and he doesn't personally know any of the other kage or akatsuki's powers.
Plus not to mention, Chiyo spoke of hanzo like she evwenly fought him several times and showed no fear or reverence talking to or about him, meaning they were around equal power. Judging from all factors, Hanzo could only be considered low-mid kage by analyzing his hype.