it does include the 3% from backlash talent, and freetrial, it's roughly the 170 hit mark where destruction can become more viable than afliction. you don't need 202 hit, though it is obviously the aim.
the crit mark though i've lowered a bit. at 170 hit i'd say 18% crit is the mimum. at 202 hit, 15% crit is now the minimum imo (all crit values are not including devestation). the decrease in ISB uptime isn't that major between 15-20% crit (not including devestation, so 20-25% including it) so no real worries.
reason i've been coming to this conclusion is due to my recent rush to collect spell haste, which has lead me to move from 23% crit (before devestation) and 0% haste. to 16% crit and 17% haste. the overall dps increase though has been massive.