The best replacement for usb 2 is firewire.

The best alternatives to usb 2 are rated as following:
★★★★★  firewire
★★★★  usb 3
★★★★  usb 1
★★★★  3
★★★  1
★★  ethernet
★★  esata
★★  3 cable
★  usb
★  3 flash drive
★  firewire speed
★  firewire 400
★  firewire 800
★  1.1
★  1394
★  usb 3 speed
★  gigabit ethernet
  usb 1.1
  usb 3 cables
  usb3
  ieee 1394

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

Other search terms related to usb 2 and their ratings are:
★★★★★ usb 3
★★★ usb 1
You have in mind a companion for usb 2 and it is not yet here? Propose!



Google Trends

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