I think you are correct on his example. I checked and Jeremy has clearly stated that each individual attack within the attack action can be substituted with a grapple or shove. This makes sense ... There was an effort to reduce complexity so that a DM may lead the combat in an organized way (that can keep the narrative). OA and other reaction attacks have the potential to chain, etc. Whereas extra attacks are simply the same attack choices at the same time. I do love the simplicity of 5e: slightly over simplified, but in a way that a DM could now bend the rules in a safe way to help the narrative.. (trying to avoid having the rules force complexities that take away from both the narrative and from DMs that don't have a desire to be rule specialists)I believe that might refer to "I grab you. Oh you broke free? I grab you with my OA."
He also stated that fixes to tweak/balance feats would not be practical within the current edition, these things are done when creating new editions.
Bugbears have reach on there Grapple attacks. Worth noting.
Eh, it allows you to grab and drag without provoking OAs from an adjacent enemies. HopefullyYeah but it actually is pretty useless. If you read the feature description-- the reach is only while attacking, and only on your turn. By a strict reading of RAW, as soon as the grapple is made, the grapple breaks as they're no longer in your reach. By a slightly more lenient reading for the rules, the grapple breaks as soon as your turn is over. Either way, not great.
One of the problems is that Shapechange has a Concentration requirement, and at that tier, anything worth grappling is going to be hitting you hard while you are doing it.