The best replacement for usb 3 is usb 2.

The best alternatives to usb 3 are rated as following:
★★★★★  usb 2
★★★  esata
★★★  thunderbolt
★★★  firewire
★★  firewire 800
★  ethernet
  lightning
  firewire speed
  gigabit ethernet
  sata 2
  sata ii
  light peak
  thunderbolt speed

Your alternative for usb 3 is not listed? Suggest!
Speaking about usb 3, one probably shouldn't forget about usb 2.

Other search terms related to usb 3 and their ratings are:
★★★★★ usb 2
★★★★ usb 2 cable
You have in mind a companion for usb 3 and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of usb 3 in all years. Click on graph for more.
usb 3
usb 2
esata