I just bought the Acer Predator Helios 300 a week ago, and when I play games like FFXIV, I would get stutters or slight freezes that last for like 4 or 5 seconds.

Is this because my laptop is running hot? It gets to like 80 Celsius. I'm wondering if I should return it. I expected this laptop to perform well.

yea alot of these gaming laptops cannot keep cool its pretty common

maybe try lowering ur grahics or cap ur framerate

80 seems kinda low for a laptop to throttle that hard, but yes usually laptops have heat issues. Like Haj said, try lowering settings, specifically things like shadows and background eye candy.

Also... use your laptop on a hard surface. Don't sit in bed, with it on you lap and covers or clothing blocking the air vents.
Try to keep room temperature at 65-70F as well.

what is getting to 80 c? cpu? gpu?
what are you using to monitor temps?
did you clean out all the bloatware?

What is the point of paying for a laptop that retails at $1300 if it can't play a midtier graphic game at high settings well?

I'm using their Predator cool fan program to monitor temperature and adjust fan speed.

Other than that I removed all the Acer bloatware manually.

There are uses but the majority of the time you are going to find that a desktop would have been a better option.

Mobile parts (lower TDP and therefore less performance), thermal issues, overall power constraints (hard to push 500+ watts thru a tiny laptop power adapter for extended periods of time)

Is it normal? Of course it's normal for your computer to freeze and stutter. It's completely normal for your car to stall and break down on a weekly basis too.