You can improve Wyll's AC pretty dramatically if you take moderately armored at lvl 4. You get a +1 dex with that, so dex 13 -> dex 14, for a +2 AC. You also get to wear half-plate or scale+1 (both available in game) for a base AC of 15+dex mod (17 total). Compared to the best you can get without the feat (mage armor + dex mod = 14) that's a hefty improvement. Moderately armored also gets you a shield, for an additional +2 AC (which means he hits 19).
That means that he is not a wet tissue paper that gets hit when something looks at him with mild anger.
