Works great right up until it explodes kn the second round of taking fire. Or you get behind it.
Are you talking about the YV-666?
If so, you're saying you're doing 12 points of damage + whatever the YV-666 rolls with its 1 defense dice in two rounds? With what ?
The vesery D + Ryad PTL /7 + one /7 does 7.875 damage per Turn to that YV-666. At range 2. At Range one you do on average 10.25 Damage and have a reasonable chance to party poop in a single turn.
The more defensive Vessery + Ryad + Onyx full /x7 list does still over 13 damage on average within two turns to a 1 agility ship even with a defensive focus token. No big deal.
Even Soontir, Inq + Palp do it actually and we all know that Soontir's offense is on the weaker side of things for a 35 point ship. Though it is so close with just 12 damage on average that you not expect that result as variation should be high enough to bite you in nearly 50% of the cases.
edit:
In general I think you misunderstand how vastly your damage gets improved from having focus + target lock especially against one or zero agility targets. .