The real problem isn't the space the OS takes up, but the "Other" usage that seems to accumulate irrevocably over time. It's been a known problem for years and has never been addressed or officially confirmed. It can quickly consume even the highest capacity devices, and unless you're savvy to the problem the only solution appears to be to buy a larger device next time because you somehow messed up your phone.
The other problem is high capacity devices themselves, which command a large up front premium but also require a monthly fee to back up since Apple only provides a small amount of iCloud backup space for free. You might say that it's obvious that a company should charge more for more backup space, but then why is the first 5 GB free? When you're paying an inflated price for additional capacity up front, shouldn't that also cover backing up that capacity, especially with the collapsing cost of transit bandwidth and server storage?
There are reasons one could bring a suit against Apple, but small percentages of additional OS usage don't seem like a compelling one.
The real news here is that Slashdot articles continue to decline in quality. Hacktivism sounds exciting, but these guys are just script kiddies with a No War sig. Yesterday alone they defaced 296 sites, none of which had any political significance. They happened to find an old PHP application on a backwater NASA website (the Aura Validation Data Center), and they took the opportunity to step up their normal text sig to include a graphic picture.
The only reason that this is newsworthy is because Slashdot made it newsworthy. The greatest impact came not from the script kiddies or their vaguely political scribbles, but the deluge of the Slashdot effect on some poor iMac in Alaska.
"Only the hypocrite is really rotten to the core." -- Hannah Arendt.