Im Japanese so my English is very bad sry.
You dont need crit in this patch.
And there is good synergy between mf and cooldown build.

This build is not assassin, just deal damage to tank.
Stay with your support, and use ult after enemy tank's initiate.
Enemy's damage dealer cant come over mf's ult, so your team can kill enemy tank first.
Then, play like normal adc, but this build dont have burst damage.
So cant win in 1on1 battle against enemy adc.