I think one of the tricky aspects of dealing with skill speed in these equations is finding the optimal number required.
I, for the life of me, can not get 9 hits in with any less than 400 skill speed. While at our cabin over Christmas, this number was an atrocious 419. Due to different latencies and connection issues, there can only be an estimated number for the perfect skill speed.
I can fully agree that 390 should be the assumed value though.
The more difficult to calculate part of this equation is valuing skill speed as a DPS loss. In my situation that requires 400 on the button, a skill speed of 397 has virtually no more weight than the base value of 341, and in all reality, is theoretically a negative weight for berserk because it puts me closer to a completed GCD cycle than a lower value, effectively increasing my pacification time.
I think the ideal way to value Skill Speed is probably having two values - one for out of defiance, without the use of berserk, yielding a lower value, and one for in defiance without the use of berserk, yielding a higher value.
This would create an unbiased weight due to pacification, and will give a proper benchmark for comparisons to det and crit. From there, the player would do their own required testing to determine the skill speed they require for a 9 hit combo.
