I'm with you on this one. The Twins have actually made some pretty significant 'investments' with a few of these guys--1st round picks for Guty and Waldrop, trades for Oliveros and Guerra , and Capps for that matter. As you've stated before, if the Twins are in contention, they'll definitely go get more bullpen help. If not, these guys can get some low-intensity innings in.
As far as Capps goes, yeah, an overpay (in hindsight), but I don't think Madson is twice as good or that Papelbon is 3 times as good as Capps. For the Twins, they maybe thought better to go with the devil you know than the devil you don't know.
And, I know its just me, but I'm tired of hearing how the Twins could've had a different closer + a draft pick. The Twins have five high picks already and will owe over $12 million in signing bonuses, highest in the league.