The way I see it, Spiller fills the role of RB and WR(which is a need). Chan wants to put his stamp on a certain style of offense, and Spiller is going to play a pivotal roll. Whether people feel its a need or not, he offered great value at the spot he was taken, and gives us great flexibility to move Marshawn for more picks in this supposedly deep draft.
Who knows, after the season starts and a contenders RB goes down, Lynch's value will be higher in picks for next years draft.
Either way, lets let this play out as we have 8 more picks.