I don't use thickeners in my stews. Yet my stews always come out thick and flavorful. My secret? I puree the veggies along with the stock. This means I fish out the meat (I keep the meat cuts big) in the middle of stewing (but before adding any ingredient that must remain whole), then I use a stick blender to puree all ingredients (you have to remove bay leaves and such.) Then I add back the meat (slice them smaller if necessary) and add the stuff you want to stay whole like buttom mushrooms, olives, chorizo slices or chickpeas. When done, rapidly cool down the stew and refrigerate overnight or freeze for later. The flavors will have combined by the time you reheat the stew.