Alot of what you said were his problems can be directly linked to playing with Leddy. He was trying to do too much.. which, is understandable when you're playing with someone as young as Leddy was/is and that pairing just wasn't working.
Majority of his turnovers happened with Leddy not even close to play
Seriously Leddy was covering for Oduya more often then not in playoffs
Staal has what to do with Kruger's horrendous playoff?
Staal's defensive prowess is being painted as the way to fix our team defense. Kruger can play defense and had a poor playoffs. Staal can also play defense and had a poor playoffs. The marginal difference between the two isn't worth the assets.
If any of those three sign for sub 2.75 or even 3 mil, then you've got a case. It's really not a strong FA crop and mediocre players are going to be vastly overpaid. Oduya is a bottom pairing puck mover who gets PP time. As long as he's paid accordingly, it's a good re-signing.