Haven't read closely on it, but I've seen plenty of articles about the lack of effect we'd see over killing off mosquitoes. I have a feeling that, along with what you said, it's because they're tiny.

Consider the dragonfly. They hunt mosquitoes efficiently. But relative to their size, a mosquito is like us eating a candy bar, or even less. Meanwhile, they could snatch about anything else and it would be like a 3-pound steak.