i've created a sim of our economic rotation
10 min fight, casting only LoD, EF, HS and HL
no dp, no 4pc: 44.4 LoDs
no dp, 4pc: 46.6 LoDs, 11.6 EFs
dp, no 4pc: 58.9 LoDs
dp, 4pc: 67.7 LoDs, 15.6 EFs
without dp and 4pc we will cast finishers 8.9% of the time. we use LoD every 13.5 secs on the average.
with dp and 4pc we will cast finishers 16.7% of the time. we use LoD every 8.9 sec on the average.
I dont think it's worth using DP over HA even with 4pc. The difference between 4pc and dp+4pc is 21.1 LoDs and 4 EFs. using HA 5 times during a 10-minute encounter will give you about 16.7 extra LoDs, so by using DP over HA you get 4.4 LoDs and 4 EFs. HA on the other hand gives you a 30% healing bonus to HS and HR and a controlled burst.
But without DP our 4pc doesn't feels so powerful, it just gives 2 extra LoD and 11.6 extra EFs, or rather WoGs, since 1.2 EF/minute is not enough to take EF over SS either.
I guess we should definitely ask blizzard to buff LoD to 10k since CoH, uplift and HRain heal for 10k each.
http://ideone.com/1V5rbo if anyone ever wants to check that