something that made me think of, I wonder if for some races rather than restrict an item make it so there is an additional cost to it. Basically you make it so that particular types of races have an additional cost to using particular items unless they have an immunity to the costs. For example what if when spider buys the lace it has a faster fall speed (ie higher gravity) due to its inability to handle the weight of the item.

In theory you could apply things like this to other races in order to establish more advanced item balancing on a per race basis rather than just restrict it's use. Basically you make items something that not only can easily just beef you up but may come with an additional cost depending on the type of class you use it with.