There is a distinct 'bad guy of the week' feel, and there have been a lot of problems with the episodes airing in a different order to how they are written, but season 4 is doing a good job with continuity so far.
People who think it isn't as good obviously haven't seen some of the episodes that make season 2 look less awesome. And the last couple of season 4 eps are going to be so great that it's not funny.
You can sit around and be negative about the lack of a bad organisation and the way that the missions don't relate to each other, but what could the writers do? The show wasn't working in season 3, or getting enough viewers. As long as the characters are there then people will find something to like about the show.
[/end rant]
I'm quite sure that Seven plan to show it during the second half of the year. It's disappointing that they didn't try to show it earlier though...who needs All Saints and Blue Heelers?