Let’s be honest, while you do hear some people say they like Locke, he’s not exactly the most popular character. (I actually went on a little rant in a thread last week about him)
In Halo 4, we had Palmer. Also, not a very popular character. (Yes, I know there are exceptions among the community, but again, they’re clearly not the majority.)
Now in Halo 5, Palmer has been relegated to very minor appearances, at least once as just a hologram. Do you see Locke meeting a similar fate in Halo 6?
You have to admit, they have a lot in common. Both are obsessed with duty and following orders. I think Palmer only ever disobeyed anyone in the comics. Both have little to no character development in the games they have their largest role in. Is 343 trying to find a way to make a character of this type that fans will like? I’m not sure they could really succeed. Personally, it seems odd that they’re willing to pull lots of great, developed characters from the extended lore (namely Blue Team) but they didn’t think to do so for the leading role of Halo 5. They didn’t really need to invent Locke.
For example, take the Kilo-Five trilogy. Without chancing any spoilers, there’s a bunch of ONI operatives and ODSTs from that story arc that would be perfect replacements for Locke. They’re skilled enough for it to be perfectly justifiable that they were drafted into the Spartan-IV program. They’re “soldier” enough that the whole blindly-following-orders motif could still be used, but they’re also much more developed, (three books worth of development, in fact) and just flawed enough that they could simultaneously feel much more human, and less robot, than Locke. (Let’s face it, Locke was written as more robot than the Master Chief has ever even been suggested to be.)
TL;DR - Will Locke become yet another minor character in Halo 6? Should 343 stop trying to create new characters and start pulling more characters from the very extensive lore that already exists?