In a small bowl, mix salt, black pepper, dried thyme, dried rosemary, minced garlic, onion powder, dried oregano, and smoked paprika. Rub the spice mix evenly over the tri-tip roast.
Place the seasoned tri-tip into the slow cooker. Carefully pour beef broth and Worcestershire sauce around the meat to keep the seasoning intact.
Cover the slow cooker and set it on low for 6-7 hours, or until the meat is tender and easily shreds with a fork.
Remove the tri-tip from the slow cooker and shred it using two forks. For a sandwich option, lightly butter and toast buns, layer with shredded meat, and top with a slice of Swiss cheese; place under a broiler just until the cheese melts. Serve with a small bowl of the strained cooking liquid as a dipping sauce if desired.