If you like, after you remove the roast from the slow cooker, turn to high, cook and reduce the sauce for 10 minutes or so before serving. Or you could transfer the sauce to a saucepan and cook it on the stovetop, or you can just serve it as is.
Also, if you're not a huge fan of garlic, you may want to cut back on the number of garlic cloves, but with the long cooking time, the garlic gets very mellow and almost melts into the meat.