It looks to me like Tolliver is a natural back-up to our edge routes designed for Marshal and Jeffrey who are similar physically. Ideally we would have one more of those in training and two in the slot/return man profile.
Wilson might solve that and allow us to keep just 5 because he can do either. I think Emery is a fairly complicated mind, and he likely evaluated depth of WR in general across the NFL before deciding to cut Earl. When you can get similar production for cheap all over the place it makes no sense to pay for. Emery is very good at WR evaluation so I assume we will always have a full deck of talent on cheap contracts waiting for the day that will make us all cringe.
In my opinion, Wilson and Tolliver are both good finds.