I think most of the "classic" attractions need to be either replaced or updated. Walt wanted his parks to "never be completed" and to be constantly growing and changing. He referred to Disneyland as a "living thing". I honestly think if he were alive today and could see the parks, he'd be rather disappointed by all the attractions from his time that are still standing. I think he would say, "Why haven't you replaced that old thing?"
Mr Toad's Wild Ride
Haunted Mansion
POTC
If YOU HAD WINGS
Space Mountain
The Enchanted Tiki Room (original)
IASW
Carousel of Progress
The Walt Disney Story on Main Street
Horizons
World of Motion
Kitchen Kaberate
Journey into Imagination with DreamFinder and Figment
Spaceship Earth
Cranium Command
The Great Movie Ride
The Backstage Studio Tour (original)
The Animation Tour (original)
Star Tours
Let's make it simple. I Love every Disney attraction EXCEPT:
Under New Management (I will not call it Tiki Room)
The junk in Chester and Hester's Dino-Rama
Tarzan Rocks!
Test Track (bring back World of Motion!)
The Original Universe of Energy
Imagination!/Journey Into Your Imagination with Figment (bring back the original!)
and everything in Paradise Pier except California Screamin'.