Best archer builds are 18/21 or 21/18.  Each point into PD increases damage by quite a bit, but you need WPF to shoot quicker and be more accurate.  
15/27 build is probably fine, but the 27 agility is NOT going to make up for the 3 athletics.  You'll be much quicker with a 21/18 w/ 6 ath, or a 18/21 w/ 7 ath.