>>18301625>>18301636>>18301713Masquerain gets a good movepool and a great ability. It's defensive stats are all higher than beedrill's, and it's special attack is a solid base 80, with Quiver Dance, and you get lots of high BP STAB and Coverage.
Beedrill doesn't even get Megahorn. It's strongest moves are X-Scissor and Poison Jab, compared to Masquerain's Bug Buzz, Ice Beam, Energy Ball, Shadow Ball, Scald, and Air Slash.
Beedrill is outclassed by everything in NU, where Masquerain can compete in RU or UU. Comparing it to venomoth isn't exactly fair, when Venomoth frequently finds homes in OU teams doing the exact same thing Masquerain can do but with 30 more speed.