I personally don't think the Zaitsev contract is as bad as everyone makes it out to be. Could it be a big mistake if he does flame out and hinder the Wing's ability to make free agency moves when they are competitive in the next couple years?

Yup.

But they are paying Ericsson about the same amount and anyone that watches Wings' games will tell you he is useless against any player who can skate faster than a pile of rocks. And as the cap expands, it will become more of a fair deal for Zaitsev, as long as he can still be a solid 4-5th guy. The wings are going to have 2-3 guys on entry level contracts on defense for the next two years anyways, so it is doable.