Rather than "eliminate", let's say "reduce". Not all of the options that can be specified in faces-config and web.xml have annotation equivalents.
Annotations are a mixed blesing. They cut down on the need to do side editing in a config file, but if you don't have good shop documentation and good standards, it can result in playing hide-and-seek trying to find where a definition is being made.
An IDE is no substitute for an Intelligent Developer.