Heres some history for you....
In the early 1980's (when Howard was treasurer) we experienced a wage driven recession. Wage demands where causing incredible pressures on the economy, and this was largely due to the industrial relations system. Since then, Howard has seen the need to reform the industrial relations system to be more flexible, and some say it has been his biggest political goal spread throughout his entire career.
However in 1983 Howard was no longer treasurer as Malcolm Fraser lost the election and his much desired reforms did not occur (although Malcolm Fraser probably wouldn't have put them through anyway as he wasn't as big a reformer as Howard). So Bob Hawke, the former ACTU president was now Prime Minister. With Labor's close ties to the unions, they werent going to reform the industrial relations system in the same way that John Howard wanted to.
But they did recognise the need for some sort of action, because wages were too high, and could risk causing further problems down the track. The Accords were a set of agreements made between the Unions and the Labor Government in order to solve this problem. They were a band aid solution that would solve the problem in the short term, howevor didn't provide the structural changes to the industrial relations system that were required.
In 1991, Paul Keating who was renowned as a reformer challenged Bob Hawke and became prime minister. With his new position, he was less afraid to put the permanent changes that were required in place. Paul Keating was incredibly influential within the Labor party. Even as treasurer, many say he had more influence than Bob Hawke (hence why he challenged and won - although it took him more than one attempt).
Paul Keating introduced Enterprise Bargaining which was a structural solution to the problem. It wasn't as far as Howard would have liked, but nonetheless it was a step in the right direction. Of course as of 1996, Howard was now in control, and implemented his limited version of industrial changes known as the workplace relaitons act. Howard would have LOVED to go a lot further, but for political reasons he couldn't. He had to make a deal with the Democrats which limited the scope of the reforms in order to get it past the senate.
In 2005, howard gained control of the senate, and he now had his opportunity to put forward the reforms he wanted to. These reforms are a lot more profound than keatings, and the workplace relations act, howevor nonetheless it still probably isn't as far as many people would like to see. Groups such as the HR Nicholls Society are extremelely dissapointed that the reforms didn't do more, but then they should probably consider the political implications of going further.
I guess the major issue about workchoices at the moment, is that they are a set of reforms that are designed to solve a problem that happened 20 or so years ago. There are many benefits that come from them, and personally I am a strong supporter, but I understand that when in 2006 we have a massive skills shortage problem, that it seems odd that the government is focussing on industrial relations reform rather than something to solve current problems.