Hey! great question… I’m a newbie myself, but from what I know, the gradual ramp up to an eventual 1000 validators as outlined in the original vision for the network by the core devs is to ascertain network stability rather than rush out whole hog from the onset.
So the drawback may be, the network crashes? The benefit is that more people can participate in the staking process and reap rewards. Currently staking, at least with verified/reputable nodes seems to be maxed out… thus block rewards tend to go to the more heavily invested folks. Increased validators means more little guys can get in the action. That’s how I understand it at least.