I think it would be beneficial to actually let the player build their character around a playstyle they enjoy. Half the reason I quit Horizon was because none of the combat options were fun to me in the slightest. I hate traps, I don't like ranged weapons, and anything larger than small enemies couldn't be stealth killed, so there was really no entertainment in the combat system whatsoever for me.
That way, people who just wanna shoot shit can still do that but people who find guns boring don't have to.
I understand that, what I'm saying is that from what I felt on the game I don't think they'll want you to take the bigger machines with the spear.
Maybe they could add some new tech to the spear (or a new melee weapon) like elemental damage or something that's effective against them but at the same time, fighting lesser machines and humans will be extremely trivial.