I agree with your general conclusion. However, in terms of their play, see it like this:
Thornton, Marleau, Pavelski, Couture, Hertl, Wingels, Kennedy, are playing well. On top of that, you have Nieto, who is going through a bit of a rough patch, and Sheppard, who's put together a bunch of consistent games. So, the way I see it, 8 out of the top 9 forward spots are already occupied by someone who deserves it. Then, you have to choose between Nieto and Havlat. Not only is Nieto's development an issue, but Nieto doesn't have nearly the amount of question marks Havlat has...I think TMac's assessment of why Nieto is struggling is sufficient.
So, you then have to deploy Havlat on the fourth line. He might as well bench him at that point.
As I said, I do think it will take more time for Havlat to fully recover and find some chemistry with the team. But for his own sake, he needs to find it fast. There is only so much rope that he can be given; keep in mind that he wasn't exactly super-productive through ~40 games last season.
Eventually, Burns and Torres should be healthy. Things are going to get crowded fast, and Tmac is likely going to have to address the issue of which three play amongst Nieto, Hertl, Kennedy, Wingels, and now Havlat. Day-by-day, Hertl and Wingels are starting to pull away. Havlat is going to find himself competing with a very tough group.
Even if you find 9 guys better than him, you don't bench him because he's on the 4th line. If you want to get the guy back into game shape, even 4th line minutes help.