Like Britton before him, Diekman has the same problem as everyone else on this Cubs staff--he just doesn't throw enough strikes.
They need to prioritize adding a starter and a reliever who throw strikes. Handedness doesn't matter as long as they don't have severe splits.
I'd take Diekman in a heartbeat if he's basically a throw-in. Hard to hit and throws hard. Yeah his has control issues but Duensing is dead weight at this point, so why not add Diekman to the mix as a viable option.