Suggestions for making this VGC team better?

Question

Pelipper
Item: Damp Rock
Ability: Drizzle
Nature: Bold
EV's: HP 252/Def 4/SpDef 252

• Protect
• Stockpile
• Roost
• Scald

Gyarados
Item: Life Orb
Ability: Intimidate
Nature: Jolly
EV's: HP 4/Atk 252/Spe 252

• Protect
• Dragon Dance
• Ice Fang
• Waterfall

Gastrodon
Item: Leftovers
Ability: Storm Drain
Nature: Quiet
EV's: HP 252/Def 4/SpAtk 252

• Recover
• Toxic
• Sludge Bomb
• Scald

Porygon2
Item: Eviolite
Ability: Download
Nature: Relaxed
EV's: HP 4/Def 252/SpDef 252

• Trick Room
• Recover
• Ice Beam
• Thunderbolt

Hariyama
Item: Flame Orb
Ability: Guts
Nature: Brave
EV's: HP 252/Atk 252/SpDef 4

• Protect
• Fake Out
• Brick Break
• Knock Off

Dragonite
Item: Assault Vest
Ability: Multiscale
Nature: Adamant
EV's: HP 252/Atk 252/SpDef 4

• Rock Slide
• Earthquake
• Dragon Claw
• Fire Punch

Comments

Replace Dragonite with Garchomp for better speed and typing. Give Pelipper a focus sash to let it set rain twice and 252 SpA/4 SpD/252 Spe modest to make it as offensive as possible. Replace stockpile and roost with hurricane for a powerful STAB that can't miss and tailwind to make teammates faster. Give Gyarados a waterium z for more power. Give Gastrodon a wiki berry for more healing and 252 HP/252 Def/4 SpD relaxed for more physical bulk. Give Porygon2 252 HP/4 Def/252 SpD sassy to increase both physical and special bulk. Replace Hariyama's protect and brick break with feint to break protect and close combat for more power.