Balance was the ultimate card but it was not the only (offensive) card played in every content.
I looked at parse too, and I saw several mindsets of AST : only balance, balance/spear, balance/spear/arrow...

I can tell you, I'am not from those.
After hundred of hours of AST play (every content, progress/speedkill), I have adopted this mindset : balance/arrow.
During SB, I have read an interesting comment saying that only balance and arrow can guarantee a gain of time.
Of course, I have tried the three offensive cards in every situation possible, and at the result with my observations and from website analysing raid buff, Arrow was equivalent to 75-80% of the Balance (Spear was somehow around 40%).
And the best opener my team had done is with Arrow (happened very very few times but it's there). I remember particularly on Ultima burst at the beginning of his phase because we have reach 1% below than with Balance (2-3 times).

So fishing for Balance is nice, but discard everything else is not.
Arrow was still very good and it's better to have 1/3 chance to play a card than wait for the 1/6.

It was my unpopular experience and opinion about Arrow