There is a lengthy article in last week's Education Week discussing the impact the actions taken by the Wisconsin governor and legislature are having on local negotiating relationships. (The article is here, behind a paywall.) In sum, the point is: these are relationships of some standing, and in many cases, they are good negotiating relationships. After all, these people have to live with each other; many of the examples given in the article are from small towns. The school committee has children in the local schools; the teachers often live locally; and contracts come up for renewal every three years. Whatever animus develops through negotiations, at the end of the day, you need to have a livable relationship between management and the workers.
That's been put in some jeopardy by the actions of Governor Walker and those around the country taking other similar stances. As a result of what's happening, school boards have put their negotiations on fast forward before the law takes effect. At last note, there's now a bar on enforcement, giving boards a bit more time.
Limiting negotiations to only salary necessarily makes them more difficult. If you've watched any contracts settled, usually there's something given by one party in one part for something they get in another part. If all there is to talk about is money, there's no flexibility in the negotiations.