Even with the recent (very small) damage buff it got, it's most likely terrible.
Focus Fire is, after 184.108.40.206, very good on high Impact ARs like Suros Regime. And on high RoF ARs like Arminius-D, it doesn't really affect your DPS too much, it basically transforms them into mid-tier ARs with a huge magazine.
But if your AR is already mid-tier like Abyss Defiant is? Focus Fire makes your DPS and TtK the worst in the entire game among primary weapons.
Without Focus Fire, the optimal TtK of Abyss Defiant is 0.9 second. (Mediocre already.) And, in the past, if you put on Focus Fire, it's TtK was…holy shit, 1.40 seconds.
Yeah. One point fucking four. In a game where a TtK of 1.0 like with The First Curse is often considered too slow.
If you add in the 5% bonus precision damage it got with 220.127.116.11 its TtK would still be about 1.2 I guess, since it would now kill with 7 crits instead of 8. But that's still really bad, considering that's the best it could do. It would be even slower if you didn't manage to, you know, hit all 7 shots to the head without missing the head even once. Before damage drop off.
How many times do you land 100% of your shots precision on a Guardian in-range? Yeah it's not often. (This is part of the reason why ARs in general still suck, though Focus Fire high Impact ones are more usable now.)
Abyss Defiant gives you the choice of Focus Fire or Hip Fire, always choose Hip Fire.
And in general, ditch any mid-tier 88/8 AR that forces you into using Focus Fire.