Actually, that bug doesn't strictly say that it will be fixed in FF7... just that, should an approved patch land in the near future, it will be eligible to be in FF7. Given Mozilla's new release schedule for Firefox (quarterly), I would think a patch would need to be approved pretty soon or it wouldn't make it in time. Based on this (https://wiki.mozilla.org/Releases), I would say a patch has until the 5th to get landed in time for FF7. I don't know if such a patch could be put into an Aurora or beta fix, or if it would be considered too disruptive.
The workaround of setting 'html5.parser.enable' to false is a fairly big change- you're basically trading Firefox 4's renderer out for Firefox 3.6's. In this case it's a good trade, but it could break things that were fixed by upgrading to FF4 in the first place. This is the kind of workaround that works fine now but might cause a totally unrelated problem in 6 months, because you've tweaked a more or less hidden, easily forgettable setting. You might run into a bug somewhere that most people can't reproduce. If you remember this tweak, no problem... if you've forgotten all about it, you might pull your hair out trying to figure out why your Firefox acts differently than someone else's.
If you're just an occasional NetApp admin, it might be better to change it when you need to use FilerView, and change it back after so as to not create a bizarre hard-to-trace problem down the road.
As for System Manager 2.0, I'd be interested in trying it, but for this note (emphasis mine):
Note: The Public Beta program is open to all existing NetApp customers. The Beta version of NetApp System Manager 2.0 software has to be installed only on non-production environments. Beta has a limited support on NetApp communities only.
That almost sounds like not only is it not yet recommended for production use, but that you are actually forbidden from using it in production (maybe by licensing terms or other contractual obligations).