That doesn't really rise to the level of specifying how a work product must be produced (one of the main differences between employees and contractors), only some prerequisites. (They won't even let you drive if you don't have a >2004 4-door vehicle)
You can probably make an argument that "you have to get good ratings" encompasses all sorts of informal but well-understood job requirements. IIRC, Uber has recommended all sorts of "tips" for getting good ratings - give a bottle of water etc. They also set things like minimum acceptance rates for incoming requests.
"The most useful part of the Uber guide for its drivers will probably be the advice on how to maintain a high score. Here's what Uber recommends:"
Offer passengers bottled water, chewing gum, snacks, mints and phone chargers.
Keep your vehicle clean and well-maintained.
Dress appropriately.
Open the door.
Offer to carry bags.
Take the best route.
Be nice.
Pick up the right rider.
Don't ask for a five-star rating.
"That doesn't really rise to the level of specifying how a work product must be produced (one of the main differences between employees and contractors),"
Can you please cite any case law for this proposition?
PS there is a ton of caselaw on what it means for a taxi driver to be an employee or not, and this isn't in there :)