Andean sling is pretty underwhelming compared to atlatl which is given to Aztecs. it tries to
addresses the weakness of both skirms and slingers, a weakness that can usually be solved by stand ground. Slinger could benefit from Andean Sling since minimum range is a weakness for a unit meant to counter infantry, but you are better of spending your resources on more slingers in castle age. Imperial age slingers are not worth it because they are too gold intensive and lack an elite upgrade. Skirms are just terrible against any melee units and Andean sling will not change that, the only matchup that this actually helps them against is halbs and if you are in danger of losing your skirms to halbs you should just resign. IMO the worst thing about Andean Sling is that the best way to utilize these units is too never need Andean sling in the first place. I’m not sure how to fix it add +1 attack or increase the firing rate or something.
Decrease reload speed as well as removing minimum range could be an option.
Agreed, Andean Sling rarely helps Skirmishers and sometimes can even be detrimental. If you are facing many archers + a few cavalry then it would be better for the skirmishers to ignore the closest target and spread damage across the enemy archers.
It is an important tech for slingers, especially when facing fast infantry like Eagles or Woad Raiders, but honestly this should just be built into the unit.
Increased firing speed would be a good option to give Incan skirmishers as advantage over enemy Skirms.
Not to get too far off topic, but Fabric Shields is also pretty underwhelming. I’d like to see it increased to at least +2/+2 so that Incan Eagles aren’t so far behind Mayan or Aztec (they would still lose to both, but not as badly). This would have no effect on a fight vs archers or raiding near defensive buildings, and minimal effect against enemy swordsmen (where bonus damage dominates), but it would help against other melee units like Hussars. Maybe also give their Eagles a little speed boost (5-10%) as a nod to the old Couriers and a non-combat bonus since they will remain the weakest Eagles.