When restoring a deleted page, it presents a form to put a reason for the undeletion, and below there's a list of *ALL* revisions that were deleted, with checkboxes to select each of them, without any pagination.
This presents problems with pages with lots (thousands) of deleted revisions. For example, deleting for merging histories, "accidentaly" delete a page, hide a specific revision, etc:
- If you attempt to load the Special:Undelete for that page, you may get a timeout an OOM or your browser crash/eat all your memory.
- If it even loads and you want to select lots of individual revisions to restore, you may hit the max_input_vars limit  (see bug 18687) and the selection won't be applied.
Pagination should be like page history.
Of course, pagination would be tricky for doing partial restoring, since on pagination you will lost the previous marked checkboxes. But at least the undelete page would load on pages with huge number of deleted revisions, and one could select revisions to restore in smaller batches.