Theory: FA-less Fighter/Page

Whoops. Sorry!

But, more on topic, not realizing this was an old thread, I spent some time contemplating FA while I was training.
Now, I'm level 68, so not quite 3rd job, so your results may vary, but I found that very rarely was I training anywhere that the damage difference found in using SB on a mob of 5-6 really made a difference. Moreover, due to my short range compared to a Spearman, on the majority of the monsters I'm training on, I'm not getting 5-6 in a mob, either. Maybe at MP3, the initial mob on a platform might be that big, but the difference would be negligible. To me, at least, they'd die in the same number of hits. But once that big mob is gone, you're left with groups of 1-3. And at places like V/hoodoos, or even Windraiders to some extent, Power Strike is more effective. So at least, for me, Final Attack was worth maxing. And as was pointed out by others, FA won't activate on 4th job attacks, so it's really moot by then.

you dont notice the difference because you havent had a chance to whack at mobs both with and without fa at a high enough level. once you get to an area where you struggle to meet the kb values, which are 10% of the monsters hp, then you will notice that the first monster dies much faster than the 6th. (ie... duals. still the best wk training in late 7x-8x). this is where you will cry about how much fa sucks with slash blast. but until you can extend the scenario to an extreme, you wouldnt notice. training in 2nd job is much much different from training in 3rd job. 2nd job is 1-2hko for max efficiency. 3rd job monsters have too high of hp to do that, so you have to go for highest possible dps.