There's not really much you can do to upgrade the cooling without basically re-engineering and rebuilding the entire cooling system. You could always install bigger and better fan motors, thicker and thirstier heatpipes, bigger blocks of metal with wider mating surfaces, etc. But you'll get increasingly diminishing returns, you'll gain a little more peak performance overhead, you'll add a lot of weight and noise and power drain and cost. Asus did a really good job on this one.

I'd be hesitant about drilling intake holes. It might work, but it's permanent and noticeable, be careful. They may indeed provide more spot-cooling but at the cost of disrupting the "ducted" airflow design built into the chassis plastics. So you might find your CPU temps improve by 10C while your GPU or motherboard temps scream upwards because they're behind dead-air or recirculating-air zones.

You're obviously not worried about frequent disassembly so I don't think dust accumulation will be much of a problem. I doubt those Asus dust filters really do anything useful, anyhow, since in my experience they don't seem to actually stop a dust from getting sucked in, lol. But no dust filters at all means you won't want to be using your laptop near a sawmill, lol.

The biggest source of heat in a laptop is usually the battery. Replace if it's getting elderly. Don't simultaneously charge and discharge it - meaning don't just plug in and keep running games when the battery is in the red, it'll work but it's hard on the battery and makes much heat which is hard on the computing.

The best cooling solution for any laptop is one of these. Criticize if you must, but if cool laptop is what you want then this works.