Boris Gudenuf
Deity
Fair, but realistically I'm almost positive that a bolas has a shorter range than a sling...I'd probably give it higher damage and a chance to stun the enemy.
Not familiar with the Bola as a military weapon, but generally it is much shorter ranged than a sling, but also has a disabling effect regardless of the armor or protection of the target, which could be the source of a 'unique effect' for the weapon.
To digress briefly on Slings...
Slings in general fall into two distinct categories: those that use rocks as missiles, and those that use streamlined lead pellets. The former are the cheap weapon of every sheep or cattle herder man or boy and so provide, as in the game, a 'basic' missile weapon. The latter Outrange bows, and have the added feature that the lead shot cannot be seen easily in flight, so unlike arrows, you can't dodge them. Therefore they are particularly deadly against unarmored troops and skirmishers - like archers. During the Middle Ages a bunch of mercenary English longbowmen were shot to pieces by Baleric slingers using lead shot, both because the shot outranged the direct shot of the longbow, and because the slingers were dodging the arrows while the bowmen were getting their brains splattered all over the landscape by 'invisible' lead shot.
Of course, good slingers are like longbowmen in that they require years of training and practice. That really makes them specialized troops rather than the bulk of any nation's missile troops.
I'd love to see City States provide possible Mercenary Troops the way some did in Civ V, so that we could add a City State from Crete or the Baleric Islands, both home to famous Classical/Medieval lead-pellet slingers, which would provide Slingers with increased effect against enemy Ranged Troops and a 2 tile range.