First I want to say this probably belongs in the suggestions subforum. Next I want to say that I was thinking about zombie bites early this morning and came up with what I thought could be a solution that doesn't fit zombie lore, so it could be a custom sandbox option..
I play with zombie infection turned off, I've died enough times that I'm sick of re-doing the grind for skill XP over and over and over just because of an unlucky bite, the first couple of hours of gameplay gets old eventually. Animations update did something though that makes me want more punishment for getting a bite: If you're bitten on an arm, your attack speed lowers to about half. If you're bit on the leg, you're forced to limp slower than walk speed and cannot do ANYTHING but limp when you move. No sneaking, no running, nothing, your bum leg makes you a sitting duck for zombies if you try to go face them.
And I found that I actually enjoyed holing up to let my leg heal, even if the bite didn't infect me it was still punishing for me and delayed my scavenging for a few days. If I didn't have supplies to last a few days, I would've even had to go out and put myself in huge danger to gather some, so I started thinking: What if there was a custom sandbox option for a treatable infection? If you get bit, you'd have to take careful care of the wound to avoid turning into a zombie while also potentially dealing with slower attack speeds, or a dangerous limp. The bites become survivable, but the injury still heavily impacts your gameplay and there's this anxiety of: "What if I don't clean it well enough? Will I get sick and die?"