But in PvP I tend to lean towards Haste to do the environment around it (dispels, CC, interrupts, training, etc). Don't forget that Haste stats are increased by 5% due to Affliction bonus.
Worth mentioning that haste means faster corruptions = more NF procs = more SS, and that reduces GCD = moar dots and warlock curses. While mastery increases dot ticks, but doesn't benefit in any other way other than raw damage.
This spot on,
Highlighted what I feel is most important part. Any improvement to soulburn:haunt uptime is way more than a few points of additional mastery can manage.
Basically crit/versatility is shit. For pvp multi-strike is doing quite well so I would rank it:
As far as I know in PvE: Int > Haste >= Mastery >>>> Vers = Multi > crit