Arcane Archer as a base class

[Sound of Azure]

Thanks for the edit, llamatron2000.

The class looks good to me, and I especially like the customisation you've achieved. Apart from the name ("class ability?"... how about "Arcane Infusion", "Way of the Archer", or even just "Arcane Archery"), one concern I have is the last two "Class Abilities" you gain are next to each other and break the existing acquisition pattern.

The last class feature, "mighty enhance"... I like the idea, but it really restricts what you can do. I like the abilities you have a choice from, but it might be useful to allow the archer to attune a different "bonus" by spending an hour in mediation (or something like that). It's still large enough amount of time to be impossible in battle, but does allow the arcane archer to adjust according to changing circumstances if need be.

Additionally, I'd allow this class feature sooner, but alter the available enhancements as the archer levels up (and eventually allow multiple enhancements). If you do this, you may wish to restrict the ability to a few minutes per day (split up round by round, as desired), in much the same way as the Oriental Adventures' Blade Dancer prestige class, or Complete Divine's Shining Blade of Heironeous.

If you don't want to grant "mighty enhance" over several levels, I'd move it to 18th level, making it the highest level extension of the "enhance" chain of abilities, and move the last "class ability" to 20th level, thus retaining the existing progression.

In the OP, you mentioned armoured casting being available as a bonus feat. The class no longer appears to grant bonus feats (I don't think it needs them). I would give the basic armoured casting at 1st level.

More importantly though, even if the arcane archer gets armoured casting, your class is not proficient with any armour. In fact, he isn't even proficient with bows (or anything else for that matter)! I assume it's an oversight. Could you post a weapon and armour proficiency list? For now, I'd assume the following:

Weapon and Armour Proficiency: The arcane archer is proficient with all simple and martial weapons, as well as with light armour. Arcane archers are not proficient with any type of shield.
An arcane archer's training allows him to avoid the chance or arcane spell failure when casting arcane archer spells in light armour. However, like any other arcane spell-caster, an arcane archer wearing medium or heavy armour or using a shield incurs a chance of arcane spell failure if the spell in question has a somatic component (most do). A multi-class arcane archer still incurs the normal arcane spell failure chance for arcane spells received from other classes.

Class skills: An arcane caster without Concentration, Knowledge (Arcana), and Spellcraft? I would add Profession and possibly Search as well.

Finally, I agree with trav_laney. I think good Will saves are more appropriate for this class. Hope this helps.