“Not as good as I once was… but I’m as good, once, as I ever was.”
Kraven is not superhuman IIRC. He gets some kinda buff from a potion or something, right? How then is Kraven, a regular dude who takes a potion to make him tougher, stronger than Logan? I don't see how that's possible. Imagine they're both in a gym lifting the same amount of weight, the same reps, everything the same. They do this for 18 months. At the end, despite the conditions being the exact same Logan would be stronger because his muscles tear and heal so much quicker, no?
"Kids don't care **** about superhero comic books. And if they do, they probably start with manga, with One Punch-Man or My Hero Academia. " -ImOctavius.
Most super powers in fiction tend to come with a bunch of secondary powers or self-harm preventing control mechanisms to make them work idealy.
By comparison some writers who like to present super powers themed stories as dark, depressing and horrorfying often like to leave these secondary powers out for disturbing effects.
In case of Healing Factors they usualy come with the safety mechanism, so that the powers don't block "beneficial" damage to the body like muscle build up, bone density increase, or developing resistances/immunities to diseases and infections.
Likewise the healing factor always restores the body to an "ideal" state or even to the exact state they were in before they received the harmfull damage. For example hair regrowing to the exact length it was before, instead of requiring the natural timespan to grow. Or the skin regaining it's tan. Etc.
Basicly there is a lot of "magic" at play to make healing factors more ideal and purely beneficial than they should logically be.
The game Bioshock 2 has an audio log in which a doctor described what happend when a girl with accelerated regenerative abilities jumped from a too high place and broke her legs. The result was that her legs heald so rapidly that they couldn't right the bones quickly enough, resulting in them healing into a deformed state, requiring painfull re-breaking and setting.
Meanwhile in most comics when Deadpool or Wolverine receive broke bones they either snap back into the correct shape by themself or they somehow don't heal until the person can manualy right them. The later also showcases the potential of a conscious mental control over their healing abilities.
I haven't seen anything from Kraven to suggest he's stronger and faster than Wolverine. If it's because he's able to keep up with Spider-Man then so has Wolverine. Besides, Kraven already lost to a powerless Old Man Logan. No way he should win against a "younger" stronger, faster Wolverine who's healing factor is insane these days.