New Page Dialogue Slow to Select Parent

I have a blog with a few hundred posts (and growing) set as children to the home page. When creating a new Post, the drop down for `Parent` takes ages to load and has an adverse affect on the UI of the form. Performance is fine until the drop down is active.

I can think of a few work arounds:

1. Limit how many pages are available before searching or using a plain text input
2. Providing some mechanism to designate pages that can be parents (explicitly in frontmatter, perhaps?)
3. Allowing some way of creating a page directly under a specified parent (perhaps as an interface plugin to add another button)

Thoughts?