It's possible to get a very decent AC with an archer. First I can figure is -7 for SoA (within chapter 2) and -10 for ToB. Then there's the armour of faith priest spell, which will potentially absorb 25% of damage (fill all your level 1 slots with this), and then there's the certain ToB HLA which will boost this substantially further.
Sure, your enemies will attack you with a +4 bonus if you have your bow equipped, but there is a simply solution....switch to a melee weapon when the enemy closes in. It won't always be feasible to run away, often you will find yourself surrounded or battling in a small area.
The archer may only be allowed to spend 1 point on any non-ranged weapon, but this only means losing -1 to hit, -2 to damage and -0.5 APR. The archer will still recieve the bonus attacks from levels 7 and 13, and the 1 point will nullify the -1 to hit and -1 to damage penalties, as well as allowing the warrior APR bonuses to apply to the weapon (otherwise you will be limited to 1 APR - the 1 point is still very handy indeed).
Simply equip a larger 2-Handed weapon (Halberd/2-H sword/Powerful Staff), and you can use the quick weapon slots to rapidly swap between them (messing around with shields/and dual wield combos every time using the inventory screen will become tedious). Plus, you can invest a further 2 points into 2-H weapon style to recieve massive speed bonuses, recover a +1 damage bonus, and get an improved critical. An archer can still be a formidable melee opponent

.