Until we know exactly what Air Berlin and Lufthansa/Eurowings intend to do it is difficult to assess but I would expect the key criteria to be
1) If the slots have been allocated to Air Berlin and are leased to Eurowings along with the aircraft then it could be seen as a marketing agreement along the lines of "Eurowings by Air Berlin" rather like Hop took on a number of local French carriers operations.
2) If however, the slots are definitively transfered to Eurowings by some deal and are at slot restricted times and when Eurowings already has a near-dominant position on arrivals and departures at such times then Lufthansa could be requested to release some slots at such times to allow another airline to compete on critical routes. Note that domination at an airport is not the most critical factor but rather specific routes from the airport. However, even then, if you look at the French market, despite the attempts of Air France to contain Easyjet operations, they are now all over France and apparently quite successful, so it is debateable whether not having say peak-hour slots actually prevents an LCC from providing an adequate low price offer (not having any at all is different),
As far as I am aware, the authorities are not obliged to look at the longer term (e.g. is this just an marketing agreement and not a direct transfer of Air Berlin operations to Eurowings) if that is not stated, and some words used could suggest that it is just that. I suggest the test is whether the Air Berlin brand will completely disappear on the operations of the 40 wet-lease aircraft.