The new search suggestions is quite a nice thing, but there is a usability flaw concerning special characters in german (umlauts, ß), french (accents) and very likely a lot of other languages.
Since it is very unlikely that a german user enters an 'ä' accidentally instead of an 'a', i think he can expect to be presented suggestions which start with the exact character sequence he typed. This is not the case, like the following example on de-wp shows:
If you enter the characters 'fü' in the searchbox, the following suggestions appear: Fußball, Fußball-Bundesliga, Fußball-Weltmeisterschaft 2006, Fußballverein, Fußballtrainer, Fulda, Fußball-Weltmeisterschaft, Fußball-Weltmeisterschaft 2002, Fußball-Europameisterschaft 2008. Mainly lot about soccer/football (Fußball in german), its coaches and championships, and one town (Fulda). Only in the very last place, usually not visible if the user does not notice the scrollslider, he will find the word 'Fürst' (sovereign). He will not notice that there are a lot of other articles starting with this sequence: Fürth, Fürstenfeldbruck, Fürstenwalde, Führer, Fühler and all the principalities called 'Fürstentum xyz':
Interesting enough: If you start typing 'Fue' (with 'ue' being the standard transcription for 'ü' when your keyboard does not have the umlauts on it), you are immediately presented a list with 'Fü'-words. This is really handy for people who have no ü on their keyboard, but it is very unlikely that it comes to a german/swiss/austrian users mind that, in order to get better suggestions, he has to use a foreign-language-trick when he browses 'his' wikipedia with 'his' keyboard.
You'll find the same behaviour on the fr-wp, sv-wp and a lot of others.
So here is my appeal: Please change the search-suggestions in a way that Articles starting with the exact sequence (e.g. when using special characters) entered are priorized over those who are similar to a possible transliteration of the special characters.