to add a few more points...
watch your mana bar go down faster
watch you have to waste more gems in spirit instead of througput stats
watch you overheal more in HC raiding
watch your IH and premtive IH shielding be much worse
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but it also makes those hp spells weaker by lowering the absorb they do. even LoD in this tiers h tf gear is going to on average raw heal for 250k + your mastery %.
what you said is also basically no different then what haste does now. its why i an others keep saying that haste in 5.4 is hardly any different then wanting to do it in 5.0-5.3.
to go even further, the lower HS cd doesn't matter anyway. due to other spells also being faster it'll still be hs hr hr lod (or a judge/cs instead of a hr) just like it is with 2k haste on live (and more so forced if hs crits). and you'll often want to LoD at 3hp when the dmg matters. you could also do hs hr hr hs lod but you can do that with 2k haste live too. not to mention that might just end up in a rotation with hs as 2nd or 3rd spell so doesn't matter.
it all just leads to the conclusion that haste wont effect things in 5.4 any more than it does now in throne of thunder. i understand that some people don't like 45%+ of our healing being IH on fights but feel like jumping to conclusions way to fast about haste over a minor hs change that really doesn't alter much of anything.