Hi, I want to make a knife for TF2 and here are some suggestions maybe good!

Suggestion 1:

Speed Knife/ The Fastly Faster Knife
Pro:
+ 20% of movement speed on backstab for 3 seconds.
Cons:
- 10% of default movement speed.

Suggestion 2:

The Cloaken Knife
Pro:
+ Each backstab gives 15 of knife's mimetization (max 100).
+ With full mimetization, an invisible backstab can be done.
Cons:
- Missing a backstab deals 20 HP, and the knife's mimetization will be resetted.
- On max knife's mimetization, the invisbility will be activated, and the player is forced to use only the knife until death/backstab.
- Deals 5 HP every second while invisible.
- Any watch cannot be used.

Suggestion 3:

The Chainstabber
Pro:
+ On backstab, if there's an enemy nearby, the player will jump to him causing a possible backstab (the player does, not automatically, so good reflex will be requested).
Cons:
- If the player miss a backstab, the knife will breaks.
- On chainstab executed, the knife will breaks.
- 300 seconds until a "new" knife.
- Razorback can stop the chainstab, causing the knife to breaks.

What do you think?

I think Suggestion 3 is too op.