You can't keep everyone! If the Packers had to get rid of a WR when they were all healthy, I'm not disappoint they got rid of Davis, who like Janis, despite being a STs stud, didn't have a strong case to be resigned and he was going into a contract year.
So it was basically Allison, Davis or one of the udfas whom are in their first contract years and showing more potential than Davis did in his 3rd contract year on offense. I guess one could argue Kumerow too... but that seemed unlikely.
It's only now that a number of the WRs are injured, do we really wish we had Davis...
As far as the return game, if the offense and defense are going, all you really need to do is be smart and have no mistakes. And it's not like a great returner would have great blocking right now anyways... and some weeks it seems like about half the above average returns results in some sort of a flag pushing it back.