The maximum charging current in the USB specification is 900 mA. The needs of devices jumped far ahead of the specifications.
A later addendum called the Battery Charging Specification was added in haste in December of 2010, long after Apple's iPad 2 had been designed months before and had already hit the streets, with many of their computer models also having been updated to charge them months prior to the device hitting the street, since that hardware development work started far earlier than the iPad 2 release date.
The USB 3.0 spec (and all USB specs) includes the concept of digital negotiation between the device requesting power and the host device in 100 mA increments. A "charge unit".
Various schemes for supporting more than the six maximum 100 mA charging units that can be requested of a standard USB 3.0 host are currently in use.
Apple's utilizes the presence of specific voltages on certain pins to extend the functionality of their USB ports on their computers, and the shorted pin idea you've mentioned has been done on some other manufacturer's charging devices.
The shorting technique shorts the data pins. It's meant for charger-only devices and data comm is not possible with simultaneous charging from a cheap device. Hard to talk when your data likes are shorted together b
The iPad was one of the first widespread non-industrial devices that needed high-current and Apple had to design their own solution because there was no standard at the time.
Later devices, such as some of the Barnes and Nobel Nook readers also had to draw high current and simply require a special charger.
While various manufacturers have decided one scheme or another is best for them, there's no ratified worldwide standard, even if USB 3.0 could truly be considered a standard. (Various host chipsets early on didn't meet the intent if the standard for things the standard was really created to solve, like data transmission speeds. Problems with hubs and power weren't straightened out for quite a while and problems still persist in the real world.)
Even powered-off machine charging was something Apple had to consider as did the chipset makers early on before there was a standard.
The answer still lies with the manufacturers really.
Does the device manufacturer provide a tested and working car charger solution they're willing to put their brand-name on for their device?
That's the best way to get it right for most non-technical users.
Or wait for the 3rd Party charger manufacturers or user community to start labeling charging devices as compatible with the device.
(Note, for the record, Apple doesn't make one either. They make the venerable airline adapter and an impressive international wall charging adapter kit, but left the liability and other problems with automotive 12VDC charging up to third party vendors.)
As far as your hope that micro-USB will fix all of your charging problems forever, don't count on it.
Just by picking micro-USB, if the manufacturer doesn't utilize the extra side connector with additional pins, they're choosing to lock the device at USB 2.0 for data rate, since micro-USB simply doesn't have enough pins in the single connector format to do USB 3.0.
Five pins isn't enough. So no 5GB/s data transfers for any device that shackles themselves to micro-USB.
So Jay, yes. It's a PITA, but not one of Apple's making.
The "standards" didn't keep up with device power requirements and all manufacturers plowed forward with engineering various solutions for their customers.
Since there are significant lead times between when a final end-product chipset that a manufacturer requests from a chipset manufacturer, to add a feature like high-current charging, and when final production motherboards and daughterboards come off the assembly line, the USB 3.0 charging spec was too-little, too-late.
In the end, tiny gauge wiring and circuit board traces amongst various other things, hampered development of high-current charging ports. That and no devices that needed it really, until iPad on a widespread basis.
USB was originally designed to replace parallel ports, traditional serial ports, etc. The fact that it has even held up this long, doing things it was never originally intended to do, is pretty impressive.
But Apple didn't cause any of your headaches with your new high current draw device. Those problems were already out there.
Ever see a USB Y-cable for portable USB hard drives in the USB 2.0 days? The drive needed more than 500 mA of power. The simple solution was to simply use two USB ports on the host.
USB shows some signs of age today. Most machine manufacturers would prefer not to have a 5V bus, and many don't, since lithium ion batteries lead more directly to 3.3V operation in laptops. Charge pump and other schemes raise the voltage to the 5V nominal spec.
If you look carefully at Apple's new connector, it's pins are wide. I suspect one of the reasons they decided to drop the Dock connector was current carrying capability of the pins. When the new connector hits the iPad, watch for a faster charge time announced as a new feature, I bet. Less pins, wider conductors, bigger gauge wire inside the cable. Just a guess.
