I think you are better putting points in Bow than Poly.
Assuming you use the point for Finesse that gets you 5%. Put in in Bow you get 5% plus crit.
This is absolutely true.
Furthermore, the bonuses from Ranged and Finesse multiply together, and you'll already have a high Finesse value. This makes stacking polymorph for damage a poor choice compared with a weapon skill.
For example, a character with 30 Finesse and 10 Ranged will have (30-10)*5%=100% Bonus from Finesse and 50% bonus from Ranged. That's 100%*2*1.5 = 300%
If those 10 Ranged points went into Polymorph instead it would be (40-10)*5%=150%. 100%*2.5 = 250%
The advantage becomes more-pronounced the more main stat a character has, and this doesn't even consider the extra damage from the extra crit chance.
The pure Finesse approach does have the advantage of working for any Finesse weapon, however, as well as additional dodge chance.
Other skill effects multiply as well. This means in cases where you will have high ground, having a mix of Huntsman and Ranged can result in greater damage than only having one. If you're also firing a Fire Arrow your Pyrokinetics skill would act as a multiplier on the entire shot too (although, I wouldn't recommend this unless you use almost exclusively Fire-element arrows).
Because of the 10 point limit on skills, you'll end up capping Ranged and can then consider Huntsman for another multiplier (when high ground is available), or Polymorph for the guaranteed, lower damage.
In summary, stack Ranged for damage. It's better than Polymorph, and more reliable than Huntsman.