Intel sat on USB 3.0 because of standards adoption delays (although, if they had submitted the standard themselves, it would currently be the only connectivity option available on all their products). Still, I don't see the problem with third-party USB 3.0 controllers. I'm not sure why USB 2.0 is part of the chipset anyway (yes, it means less chips on the board, but these aren't embedded systems here). gigE/eSATA/IDE/SATA6gbps/firewire/sound, these are all still add-on chips for many motherboards. As long as Intel keeps enough PCIe channels open for addons, motherboard makers can add as many USB 3.0 slots as they deem practical. One problem with including things on the chipset is you are bound to that number or require addon-chips anyway. Some motherboards from Gigabyte have 3 additional SATA controllers, 1 for eSATA, 1 for SATA 6gbps, and 1 that adds 2 SATA + IDE. At that point, you hardly need the 6 ports that come with the chipset. The same goes for USB. Many chipsets now come with 12 USB2.0 ports. How long before those 12 sit idle because most things get plugged into USB 3.0?
In all honesty, I wish chipsets came with nothing but PCIe connectors, and lots of them. Let the mobo manufacturers decide if they attach SATA6, gigE, Firewire, USB 3.0, USB 2.0, etc...