One of the great things about Captain Van Wynter and the revolving store is just that. The ever changing stock. However there is a downside. When ever she gets a particularly good piece of stock in, for example armor, and you are short of funds to purchase it you go out and take on a tough mission in order to gain a bit of coin. Yet when you return that great piece of armor is nowhere to be found having been replaced by equipment far below what you are currently employing.
Although it is great to have changing stock, there should be some manner to put a hold on an item, pay half, or something of that nature. Grinding is a core part of ARPGs and it is somewhat disappointing to work for a particular item only to have that item simply disappear and be replaced by gear you would no care to use at all.