Background
Special:Contributions and Special:DeletedContributions share much in common but appear to have diverged over the years. Features that were added to Special:Contributions were not added to Special:DeletedContributions, e.g. form filters (T36524) and IP range support (T357231).
Technical background
Recently, an abstract parent class was refactored out from Special:Contributions, to allow different-but-similar contributions pages to share logic in one place (T363358). This allowed us to create a new special page (as part of the temporary accounts project) that has two modes: one that queries the revision table (T363357) and one that queries the archive table (T363362).
It should be possible to similarly refactor SpecialDeletedContributions to extend ContributionsSpecialPage, and DeletedContribsPager to extend ContributionsPager, to bring is closer to feature parity with Special:Contributions, particularly with the search form filters.
(Note that IP range handling would be a bit more complicated, since it would also require continuing to store archived contributions in the ip_changes table.)