EnotifWatchlist can do wonders for users participation. It's obviously desirable to have this preference enabled (obviously opt-in) on all wikis.
It's been enabled since long time ago on quite big wikis as Commons and Meta for obvious reasons, but also on nlwiki.
I see that recently (bug 16410, bug 27003) it's been enabled also on some "random" small (content) wikis, so please consider to enable it everywhere if, as suggested by bug 5220 comment 32, there are no big load issues.
This could mean all wikis except those currently with EnotifuserTalk disabled, i.e.
'dewiki' => false, 'enwiki' => false, 'eswiki' => false, 'frwiki' => false, 'itwiki' => false, 'jawiki' => false, 'plwiki' => false, 'ptwiki' => false, 'ruwiki' => false, 'zhwiki' => false,