I look at the loss of Woods and AR really doesn't fill that loss, he can add to the O in his capacity of being a big target but Woods offered different skills that if not totally missed we will feel for sure.
Wagner on the other hand offers up a lot of stuff, he's a SB winner, he's a big time awards winner, he's playing in a spot we have rarely had such an impact player. Yes he has some age, but his abilities in the past have not been reached by any of our ILB's in years if not for ever....(not going back to like the 60's 70's MLB's we have had)
I would look at what Wagner offers up as a mentor, an on field coach, his overall knowledge vs. what Robinson offers.......Wagner offers up more IMO, but with the loss of what Woods brought, we can use that different physicality that Allen offers in exchange.