tl;dr I worry that driver opportunity, half of what makes Uber innovative, will become capped if drivers are considered employees.
My concern is that the appeal of Uber to drivers is primarily the ability to work a seemingly uncapped (for argument's sake) number of hours in a week; if they want to earn more by working more, they are able to.
As employees, I fear that the driver that has worked 40 hours in the week will not be given the same opportunity compared to the driver that has worked 30 hours in the week, as overtime costs will differentiate the two labor costs by an extreme amount. The end result will be that we have many 40 hr workers who would like to earn more (and work more hours), but cannot. I see this as especially problematic given the high cost of living in California.
I may be incorrect in some of the points above and welcome and feedback counter to it. I'm hoping for a solution that meets many needs, just like the original idea of Uber.