Level 5 isn’t level 9. Haven’t gotten to Cloak or Shoes yet but would expect to show up by lvl 5 so that part of AC is unsurprising. 15 AC Light Armor is kind of dumb though, as is 18 DEX.
Images obviously go away but undoubtedly are great (and why I keep her Trickster). SoF means no SG. Looks like no Alert feat here either, or War Caster so any damage has 35% (?) chance of burning your slot. Or I guess DEX is from item and WIS from one Feat and Book, leaving one for Alert/WC.
23 base AC is probably about three more than game could make consistently challenging, so I could see where this would (correctly) feel too easy. Surprised you haven’t seen anything that can attack that CHR/INT save though or trigger Concentration checks through damage or cancel with Silence for instance.
You really rarely have more than one dangerous caster at a time. As long as you have a character with counterspell in your party, you're not afraid of any spells.
In fact, I spent ANSI on wisdom, and frankly, it doesn't make much difference.
The gloves set your DEX to 18 and are from act 1 (purchased from the merchant). To be honest, SH is the only character that gets a lot of benefit from them. There are much better items for other characters.
The rest of the items you actually buy from the merchants located in one place at the very beginning of act 2 (literally the first place you go when you arrive in act 2).
The armor is actually medium armor. It is one of the two armors available in Act 2 that has no AC from DEX limit. It is available from the merchant in the same place as the rest of the items.
To make it funnier in act 3 there is armor with 17 base AC.
In fact, I could go for a war caster or whatever because she doesn't really use extra wisdom most of the time (the difference between 18 and 20 is only 5%) and the extra spell slots are debatable.
I kind of wasted ANSI to increase DEX by 1 but I had no right to know about gauntlets in act 1.