I agree with -Magic- in that Water-types can have a lot of fun against this team, however, another Pokémon that can destroy this team is Mega Beedrill. After getting it's Stat Boosts, Drill Run Beedrill can kill beat the whole team(barring a Scald burn), minus Aerodactyl (which can be taken care of by another Pokémon, like Suicune). This team also lacks a physical wall, so I think that Defensive Cradily can work:
Cradily @ Leftovers
Ability: Storm Drain
EVs: 252 HP/ 252 Def / 4 Atk
Impish Nature
- Stealth Rock
- Rock Slide
- Toxic / Giga Drain
- Recover
Storm Drain can shut down Water-types, especially CroCune, beats some Defoggers, like the rare Pellipper, and can put Beedrill into a bad spot. With Stealth Rocks up, Beedrill is backed into a corner.
- Use U-Turn for massive damage? You'll take Rocks damage and give Cradily a Recover into a switch
- Use Poison Jab for less damage? You get OHKOed by Rock Slide or give Cradily a free Recover OR give the opponent a free chance to switch to Aerodactyl.
Cradily's weaknesses are also covered well by the team.
Empoleon takes down Ice-types and Special Water-types that carry Ice Beam
Aerodactyl takes out most Special Bugs
Fighting-types are handled by Reuniclus or Sylveon.
Steel-types bow down to Krookodile
And, if you were to switch up the moves, Cradily benefits from a Trick Room set by Reuniclus, allowing it to kill Beedrill and set up Rocks effectively.
EDIT: Am I allowed to post multiple sets? I just thought of something else that can work with this team.