It's fairly obvious why this isn't in EA.
When you're sitting at the table, it's easy to say "my halfling barbarian grapples with Ogre's arm". It's not so easy when you have to depict that with models and animations for a billion different combinations of creatures.
Could maybe circumvent the animations problem with a special effect that shows two characters are locked together in a grapple. Not the most realistic, but perhaps better than no grapple at all