The biggest danger now is that this gives them the false impression that actually they could carry some of these players for a few more years yet. They can't, they need to rebuild, desperately.
Drogba has been absolutely immense in the European campaign this season, but there can surely be no better way of signing off than the way he did last night. If it were me, that would be his last game. Kalou, Obi Mikel would on their way too, and possibly Essien. Cech, Terry, Lampard - I'd keep them for another year, but bring in players to replace them and use this next season to effect the transition.