6% critical rate: 1.0 pDIF added to 6% of normal hits. Your base pDIF should be higher than 1.0 average, so 6% critical should be within 6% added damage.
The new baghnakhs are 4.8% stronger on damage/delay alone, for a 75 MNK.
Acc+10 means 5% higher hit rate if you weren't tricked out with accuracy, seeing as some unfortunately are, let's say 2-3% extra damage from accuracy alone.
DA+1% is almost 1% more damage. STR+3 is either 0 or 2%, unless you were a STR build, about 3/4 the time it should be worth the 2%.
Adding the damage sources (even though they all multiply), 4.8% + 2.5% + 1% + 1.5% = 9.8%, that's some crude math to show Destroyers aren't going to keep up.
On easy stuff it's different, criticals help much less, but accuracy and STR may not do anything at all.
Edit: Also if you're stacking criticals that high remember it's diminishing returns, the more you'd critical already, the less you'd want Destroyers.