Locke is master chief's replacement

First off, I don’t mean “is 343 replacing their main character”,

i mean, in the intro to halo 4, we see the interrogation, and it is revealed that somebody wants to replace master chief. Next game, this new Spartan is revealed. Coincident? With ONI around, I don’t believe in coincidences

No.

Please kill off Locke.

Why just “no”? Do you have proof?

It should be Buck instead.

Then Destiny is Halo’s replacement. (For me anyways.)

I think 343 want to make Locke his own character, not just a replacement for the Chief.
Halo 5 did not do that.

What does the opening of Halo 4 have to do with MC getting replaced by Locke?

Locke is a boring pawn, he deserve to die.