Once "gene drive" techniques are tested on mosquitoes, the temptation could be to use them to eliminate other "annoying" species. Here's what would happen.
Sharks. The rare attacks on man would no longer occur. But the food pyramid would "collapse". Fundamental to the balance of the marine environment, they are super-efficient predators at the top of the food chain: their disappearance would cause the demographic explosion of prey, which would exhaust their food resources.
Snakes. These reptiles, on the other hand, are almost never at the top of the food chain, and for humans they are more of a danger (bites etc.) than an advantage (a bit of food, a little bit of skin …). But they are important as food for birds of prey (and mongoose).
Topi. The idea of doing without it is tempting. Provided that we limit ourselves to the rat of the chiaviche, or surmolotto (Rattus norvegicus). Without this vector of germs we would have fewer infectious diseases, we would avoid damage to artifacts, food, telephone cables … Not even the cats would complain: they are in difficulty to compete with these terrible tenants of underground citizens.
Beatles. We could certainly do without them. Especially the Blattella Germanica, which conquered the world and started to live in the interstices of houses, feeding on abandoned food or waste. Its "uselessness" is due to the fact that this species has lost all relationship with its natural environment. One negative consequence: less work for pest control companies.