Feat refresh maxes at 32 or 33. Beyond that the benefit is slightly higher damage and better to hit when not using the feat. Of course, since you can use the feat every fifth turn, never miss, and maximize damage of it with Power mode, it's probably better to start putting points elsewhere. Don't worry about your armor skill, as it doesn't have a great return on points invested. Plus, as a Ranger, you're not going to have that many enemies get close enough to touch you.
Alchemy is a good skill to have, and once you learn all the cartography you can from the trainer and the book, there's still a good reason to add a bit more. At 17, you get a unique feature that's especially useful for rangers--you start to see NPCs and monsters on the minimap before they're visible on screen.
Kill 'em all, let the sysadmin sort 'em out.