Sami got a little fortunate in the first half of the season as the team continued to play pretty much as they had done under Lewandowksi. Sadly, I think the deterioration is more a reflection on his impact on the team, than the early form.
Truth is the team is performing very poorly, and has done for a number of months.
Hopefully Sami will get another crack somewhere else and learn from the experience, but any suggestion that he should come to Liverpool doesn't make any sense, based on his performance at Leverkusen, and is as PoP points out an emotional response.
I'm sure he's more than welcome back as an observer, and there would be no shortage of people who would gladly have a beer with him.