It's been eons, but I believe Kingpin started off as a villian with Spiderman, and....yes....in a few cases they actually had him fight toe to toe with spiderman. That didn't make too much sense, even though the Kingpin is above normal human strength. They basically played it off I think like he is a mutant (but not that kind of mutant), being massive but all muscle (kinda like a very large gorrilla).
I don't think he really should be qualified as "just human" in such a case, but for whatever reason that is how they played it.
They changed things a bit later when he started to mainly be Daredevils primary villian though, and DD actually defeats him multiple times. DD really should NEVER have been in the same weight class as spiderman (or even close) even though they did plenty of crossovers (don't think they ever directly fought, but...they both fought the same enemies many times.
Spiderman should be MANY times stronger then Fisk, faster then him, has spider senses and webs etc. There should be no content. I believe if I remember right Fisk even grabs spidermans webbing at one point and swings peter around by it. The difference in mass, and the fact that spiderman isn't super heavy, could make that possible, but...considering peter picks up cars and throws them etc, it just seems silly that some normal (or slightly above normal strengthed human) can do that when he can stop/catch a extremely heavy car being thrown at people or a crane falling on them (with his webbing) etc.
So yeah, Fisk doesn't always make sense, but he is still a great villian, and one of my favorites from the old day (always liked Black Cat as well if you consider her a villian...I'd say she was almost more neutral really).