One small criticism of Lallana so far is that he didn't demonstrate an ability to pick a killer defense-splitting through ball yet, like the ones Coutinho likes to do. There were a few times this season I saw him settle for a "good" pass forward when there was also a "great" pass available. Too early to judge and we might still see this dimension from him.
The Coutinho comparison is rather unfair given Coutinho has been completely fucking rubbish every time he's played this season, and Lallana hasn't.