Halo 5 miners AI better than marines

How is it that some simple militia forces on the campaign are much better than Marines in previous halo games, they are seen using group tactics pushing objects out the way and climbing crates etc simular to halo 3, can take a lot of damage and even kill prometheans on higher difficultys, it’s good to see ai in terms of halo 3 again.

Hey. You don’t mess with a group of miner -Yoinks!- armed with guns, dude.
UNSC? Pssh, Who needs 'em!?! Fireteam Osiris? HAH! It’s all about those miners.

You can’t really compare them to previous games because the coding wouldn’t have been as advanced. Although it’s always made progress from game to game. Just look at Halo 2, they added driving A.I. that was -Yoinking!- terrible and then it slowly improved in the next few games.

A.I. are still pretty dumb though. Perfect example is your spartan squad trying to revive you in campaign and just standing there or walking away.

My question is have you noticed a difference between the marines and miners in this game A.I. wise, or are they just reskinned marines?