Infraction: Multiple violations.
Message to User:
Rule 2: Don't quote a large post just to add one line of your own. Leave out as much as you can, while still making it clear what you're replying to.
Rule 6: Yes haste improves throughput. It improves your throughput no matter what spells you cast, so your point about chain heal is silly.
Let's get my personal bias out of the way here: Reaching the haste breakpoint of 916 is not very useful.
While there's a lot of good information on the haste breakpoints for getting extra ticks on RT, EL, and HR, I've seen nothing on how reaching these points would effect HPS. Here's my attempt.
I've taken a 10man Atramedes fight as an example, chosen at random.
RT cast 33 times (30.4% over-healing)
EL procs 43 times (44.6% over-healing)
HR cast 14 times, reaching an average of 5 raiders each cast (42.4% over-healing)
Having 0 haste would have resulted in a 284 HPS loss (3.2%) in this example.
Of course, every fight is different, but bear in mind that HOTs are highly susceptible to turn into over-healing.
Now I just need to figure out HPS differences if haste had been reforged to crit or mastery.
Edit: another example, Magmaw 10m
RT cast 18 times (12.5% over-healing)
EL procs 34 times (24.7% over-healing)
HR cast 8 times, reaching an average of 7 raiders each cast (36.9% over-healing)
Having 0 haste would have resulted in a 441 HPS loss (3.7%) in this example.
You're forgetting that Haste will also have a huge impact on your overall throughput especially if you are making smart use out of Chain Heal.