Swift Backhand of Justice

The Swift Hand of Justice is a trinket.  It improves haste rating.

Like all other heirloom gear, the haste rating incrases as you level up.  Now imagine using this at level 20, healing through some very bad pugs.  this haste increase, at that level, does nothing for my cast time.  actually, my casting time is exactly the same unless i do a resurrection (which takes 9.9 whole seconds). 

At level 40 somewhere, i notice that my casting speed has increased by 0.1 seconds.  yay for haste improvements!!

so now my lesser healing wave takes 1.4 seconds. and my healing wave takes 2.4 seconds.
and its been sitting there ever since.  im now level 62 and i still dont see an improvement.

I know haste rating is great, but at lower levels, it doesnt do jack.  it isnt until much later on where i can actually see a difference in my cast time.  i know 50 haste at level 80 isnt a whole lot, but almost zero haste at level 20 sure doesnt help one bit. its illogical. haste doesnt work the same as spell power.  it doesnt work the same as stamina.  the scaling is different.  if the trinket gives me hast by percentage, then that would make sense.  i'd like a 15% haste to my spells at all levels.  that would rock.