Nothing was wrong with my Galaxy S4, and yet the decision was made to completely rearrange the menus and remove the call block feature. What do they feel it's necessary to fix something that wasn't broken?
Welcome to Android Central! That would be something to ask either Samsung or your carrier--it depends on who decided to remove it. Carriers often remove or block certain functions that other carriers may still have, for various reasons (but usually due to trying to make more money by forcing you to use their own services).