It seems to be that ONLY items bought with adventure points, or items that drop in freaking PoTime, will have anything other than the standard Type 1 or Type 4 (for weapons) slots, and will only have 1 slot.
Nearly all of the upper-tier items (510+ AP) will have more than one slot and will have the higher slot types.
So, while this shield is not all that great in and of itself (comparable to a bone braced buckler) you can add, say, a +20 hp/mana item and say a FT2 item to make it a really nice shield. Of course, to do that would cost about 2200-ish AP, or 44 succesful adventures (more if the items come from different themes and you still have to "open up" an item list.)
So, basically,