Honestly, is additional hardware even required? There's a front camera that's so good that it can read speed limit signs. There's a rear camera that doesn't seem to do anything in Autopilot, but could conceivably be used to better sense traffic behind the car for lane changes (an area where the car doesn't seem do very well at the moment). It seems like the real problem now is just software optimization.
Unfortunately, it will need much more hardware for Level 3 or higher autonomous driving. At the very least, a trifocal cluster up front (one of which has 180 views so see cross-traffic at an intersection) and either cameras or radar for better blind spot detection (including cars accelerating in an adjacent lane). Most people are expecting as many as 8 cameras and additonal radar. The rear camera would be a great addition, but there's no evidence it can be used with Autopilot. And, of course, all these extra sensors will need more processing power to handle the data. The big question is whether they use multiple EyeQ3s, the new EyeQ4, or some combo of EyeQ and DrivePX. (If we knew they were using multiple EyeQ3s, for example, it will likely launch sooner than an EyeQ4 version because that chip isn't ready for mass production yet.)
That said, people having been saying Autopilot 2.0 will announced "in the next few months" for about a year now. Many thought it would be announced with the Model X deliveries. Then with the Model 3 launch. Then with the refresh. The fact they just started delivering the X in quantity and the S just got a refresh (with new features) makes me think we're looking at later than sooner.
There will always be faster processors, larger batteries, better seats, and dozens of minor refreshes after you purchase. There are no promises that Autopilot 2.0 will bring Level 3 autonomy, either. Or that Level 4 won't follow two years later. For the first time, car buyers are feeling the pain of tech enthusiasts (e.g. processors, graphics cards).
For what it's worth, I think Autopilot 1.0 has plenty of room to grow. Traffic signal and stop sign recognition and more detailed mapping, for example. But there will be very limited windows of "right time" for Tesla with the speed at which they have been progressing.