Jannie, one thing to keep in mind about Windpig's reply...
The way the thyristor flash works (which is virtually every speedlight class flash made today) is that unused energy is redirected back into the storage capacitor of the flash. So if you fire a single half-power flash, the capacitor is still HALF FULL and you can fire the flash again virtually instantaneously.
Having said that, I tried this on my own Metz 54MZ flash (yes, I know...the Canon probably does not behave identically) In Auto mode the ready light stayed lit and I could fire the flash a second time immediately after a partial output (target relatively close). But then the flash had to recycle 4 sec (using AA NiMH rechargeables) before I could fire again (a third time).
But when I put the flash into M/2, I had to wait 4 sec. for the flash to recycle before I could fire the second time.
IOW, the testing of the 430EX may be as context specific as my Metz flash was, and Windpig should probably confirm quick fire capability in both ETTL auto mode and in Manual/2 settings for you, before you jump to a conclusion.