Your right about Balance and Spear being the notable choice form HW to SB. Was I fishing for them? Not particularly. I kind of dealt with w/e ever was thrown at me as a HW, SB astro. It wasn't ideal to wait for redraw cooldowns to play certain cards. I would royal the best fit 99% of the time and that was usually for Ewer/Spire for AOE.
For Plays? Balance was usually the go to. Spear right behind that. And then arrow. Bole was pretty useless and highly situational.
Astro's skill ceiling in HW and SB (especially SB) was so high that most just threw out Balance/AOE so to avoid Draw drift. You had to be fast as an AST or you would lose your place and maybe forget to look at the Party list HP values.
I took a different approach to ASTRO. I would build my royals and plays to the team specifically. SAM or DRG Arrow/Time extend + Time dilation. BLM, SMN, RDM Balance/potency buff + time dilation. MNK, NIN, Spear/Time extend + Time dilation.
The key here was watching the battle also.
DRG used Left eye/right eye. Play on DRG.
SMN popped Bahamut. Play on SMN
NIN used Trick Attack. Play on NIN or other heavy DPS.
Follow up with arcana if RNG is bad after play.
I was surprised how well things would line up and my cards would be ready for the next burst phase after I started playing that way.
The current AST is literally a 50/50 hip fire playstyle now which is due to the previous expansions building up DPS as the main focus, and SHB doubling down on DPS hard.
AST now only cares about Ranged DPS or Melee DPS as it's quite literally all the same now card wise. 1 Draw/Play, 1 Draw,Redraw,Play, Sleeve Draw, Divination. Rinse repeat. No thinking...No strat....just DPS leading up to more AOE dps buff.
I miss Split and Royal Road as it really added a lot to the class, AST is still insanely easy to play, but now I don't have to think on my feet as much. Sad