Suggestions for extensions to be integrated

Should be merged

 * CategoryTree — may be included as optional configuration variable [disablable]
 * CharInsert — thought he was admin it was in core :)
 * DismissableSiteNotice [disablable]
 * Was implemented, then reverted. Needs a rewrite to make it less hacky-ish before being merged back in.
 * Inputbox [disablable]
 * Inputbox needs a rewrite, it's a little scary. :)
 * Nuke — isn't installed on all Wikimedia wikis, but is handy for non-Wikimedia users [disablable]
 * Was implemented in r41630 but reverted in r42117.
 * Poem — no disadvantages - r41710
 * UniversalEditButton [disablable] - r41916

Fully merged
These extensions have been fully merged into core and disabled on WMF wikis (Special:Version):
 * DeletedContributions — r41178
 * LinkSearch — very useful – r40830
 * Newuserlog — but there should be ability to disable it for wikis like Wikia [disablable] – r40769

Maybe

 * AntiSpoof
 * BackAndForth [disabled by default]
 * Cite — still have some breakages and not properly handled by clauses
 * ConfirmEdit
 * Configure [disablable]
 * Duplicator — "copy" function available on most systems since the beginning of time
 * Gadgets
 * ImageMap — useful [disablable]
 * With the ability to use |link= now, probably not needed in core (see also: r41727, r41789)
 * Intersection [disablable] — a.k.a. DynamicPageList
 * Interwiki (at least the option to view available interwikis, see also InterwikiList)
 * Renameuser
 * Yeah, that'd be good.
 * Maybe not necessarily the current version, though; see also: 15212
 * SpamBlacklist
 * Tab0 (very simple usability helper)
 * Title Blacklist
 * TitleKey
 * Might want to merge this straight into the page table (as long as we get that easy schema upgrade ability on Wikimedia first...)

Should not be merged

 * Assert Edit — too specific
 * Extension:AntiBot — zomg secret
 * BoardVote — Wikimedia-specific
 * CentralAuth — not includable
 * CheckUser — should not. There are laws in some countries forbidding logging of IPs, etc.
 * CrossNamespaceLinks — even now it is useless
 * EasyTimeline — while it is in Perl
 * ExpandTemplates — doubtable usefulness for usual user
 * FixedImage — Wikimedia-specific
 * OggHandler — external dependency
 * Oversight — to be deprecated by rev_deleted
 * ParserFunctions — ( diff )
 * SiteMatrix — Wikimedia-specific
 * SyntaxHighlight GeSHi — external dependency
 * TorBlock — needs cron
 * User Merge and Delete — causes irreversible changes (deletes users)
 * Username Blacklist — redundant to features in Title Blacklist
 * WikiHiero — too heavy
 * Maintenance - complete and utter hack, plus a security risk since a rouge admin could screw up the site via it.

Things to split out from core into extensions

 * Math rendering/texvc
 * It's a bit silly to have in core distribution, most people don't need it and it has lots of external dependencies.