If anything trackers knife is leaning more to too strong rather than weak.
The smite sucks, yes, but the vision control it gives is pretty strong, it's basically a sightstone built into a jungle item that's far more affordable and earlier to get than sightstone. Being able to deep ward jungle and top side like a support makes map control completely in your favor, while red/blue is for actual fighting, ganks, and dealing damage, none of them actually say "win condition" like trackers.
"GL ganking my mid laner, I'll just put this here for the next 2 minutes"
The only buff that trackers could get is a smite that when used, turns the smited monster into a sweeping lens (not literally), but idk if even that is balanced. Would be funny seeing rift scuttle clearing wards or knowing when your raptors are warded by the mid laner.