Is this Jive Cloud? I have not noticed such a behaviour in several jive instances, so please check jive logs for this...
In my Sneak peek of the new awesome discussion tile (custom view tile) I make a batch rest call to get 1000 elements (when the user configured it to show 1000 elements) which is quite fast with exactly this approach...
What are the response times exactly?
You could directly get the *rendered* html content with the rest api by using field content and build the index from this information...