I love the idea of the new build mode for marketers and was about to set up my client's site to use it, but:

1) It's not possible to add components to component slots in Build mode.

2) Components can only be added to page slots in Build mode. Adding new components to existing pages would be more important to us than being able to create new pages, so we need the flexibility of adding component sections anywhere on the pages.

Would love to see these limitations removed from Build mode--too many guardrails in Build mode I think would often result in Marketers working in Design mode where there are no guardrails.