Selenium RC had many limitations which eventually led to selenium WebDriver being created.
See the major differences between Selenium RC and WebDriver:
Selenium RC architecture is difficult because it requires an intermediate RC Server to connect with the browser. The RC Server is initially enabled until the test scripts start operating and serves as a mediator between your Selenium commands and your browsers.
In Selenium RC, when we run a check script, the following operations are executed internally.
Selenium WebDriver architecture is simpler than selenium RC.
The browser is managed directly from level of OS (Operating System). The main specifications for running a WebDriver test script are:
Selenium WebDriver runs better than Selenium RC as it connects directly with the user without any external proxy service being used. In the other side Selenium RC requires an intermediate RC Server to connect with the browser.
Selenium WebDriver is an object-oriented API, whereas Selenium RC is an object-oriented API less.
WebDriver focuses entirely on object-oriented programming languages such as Java, C# etc.
Selenium WebDriver supports operating system (OS) for smartphone apps such as iOS, ios and android, mobile. Conversely, Selenium RC does not support mobile application monitoring.
Selenium WebDriver also embraces the HTMLUnit (Invisible Browser) headless browser.