Cause if you check crit table, you may see that theres only 1 crit possibility for unaimed attack : dmg x 1.5.
So better crit is totaly useless in that case
wrong,
1-70 roll is 1,5x dmg
71+ roll is 2x dmg
without better crit your crits deal 1,6x dmg in average (20% for 2x dmg, 80% for 1,5x dmg)
with better crit your crits deal 1,7x dmg in average (40% for 2x dmg, 60% for 1,5x dmg)
in other words..
it will sometimes help you to pass roll over 70 for x2 crit dmg.. so will increase damage a bit of every like 5th burst, result will be too random :/
its better to take Hit The Gaps for +5% crit chance (CA crit mod is 10 / 2 = 5) for more reliable crit damage
and if you take both HtG and BC then you spend too much perks resulting in being too paper, thats why most of people decide between better crit and htg
Grizzan's build is good just take Bonehead instead of Bloody Mess