Really? You conveniently left out so many abusers in other weathers while including everything for Rain.
For Sun, there's also Mebukijika, Charizard, Shiftry, hard-hitting Fire pokemon (ie. Heatran and Shandera), Moonlight/Morning Sun users (ie. Arcanine), and probably more.
For Sand, although you mentioned the Sand Veil pokemon, you seemed to just brush it off, even though it's easily one of the best ways to use it. Garchomp and Gliscor are used all the time for abusing Sand. Also, what about Rock-types that abuse Sandstorm for 1.5x SpD? For example, Terrakion, Abagoora, and Cradily. There's also abuse of the residual damage which can screw with Stall teams. L2 Probopass and L1 Aron take advantage of this too.
I agree that Hail does suck, but at least it's a good counter to the other weathers, since a lot of Rain abusers lose quite decisively to Abomasnow, and Chlorophyllers do too since they're all Grass-type and as a result get murdered by Blizzard. The Sand Throwers and Sand Powerers take a lot of damage from Abomasnow too.
While Rain is a good weather, please don't sell the other weathers short, because they're still not very difficult to abuse either.