Selenium WebDriver can handle a lot of complexity in web application testing by leveraging its architecture that makes it incredibly extensible and flexible. The tool boasts an architecture that decouples abstraction from implementation, allowing for the addition of bindings and browser drivers independently, making for incredible depth of support. This enables users to automate with their language of choice, lowering barriers to entry even further. With Selenium WebDriver, developers can write tests in the same language as production code, placing it in the same version control system and tightening the feedback loop from weeks to hours. The tool can also improve coordination between developers and testers, create system demos, and generate a visible display of functional or acceptance testing. By leveraging Selenium WebDriver, organizations can differentiate themselves by keeping up with browser proliferation while delivering high-quality web applications.