We're adding the 2 chord to our set of temporary tonicization tools (feels weird to call it a modulation tool, but that's okay too?......hmmm.)

7 and 2 are both inversions of the traditional dominant 5 chord. 

But since we're ignoring inversions:

•  5 will be used mostly as part of cadences involving 6 or 4

• 7 and 2 can now substitute for the '5 to 1' bass motion