Why was I so much better at the beta?

Games Halo 5: Guardians
#1

I just stumbled across a picture of my stats before the beta ended in Arena and I’ve got:

KDA of 8.4, 1074 kills / 562 deaths.
69 games played, 45 of them won.
Game time 10h 3m

Now to the final game in Arena:

KDA of 1.2, 1134 kills / 919 deaths.
99 games played, 56 won.
Game time 13h 30m

Why such drastic change? Aim assist completely turned down? Small radar? Unfair match up system?

#2

I’m thinking aim-assit. I had to adjust too

#3

Because the crutch aim assist is gone.