I think suing because of the Nero would be an open-and-shut case, honestly. Low-slung chassis with battery-boxes on either side, motor on top, long-travel cantilever suspension front and rear, remote-locking diffs...the Nero is basically what would happen if someone did an E-Revo conversion to a Summit.
Being able to sue because of one specific design feature that has existed for decades is absurd, though. In my mind, if there's been a violation of intellectual property, it's because Hobbico produced a vehicle that very closely mimics the Summit's overall design, not just one easily-recognizable feature.
Wait you think this:
Looks like this?
Aside from the suspension I can't see it.
Let's take a look at the chassis:
I Think a much more compelling case would be the new 4tec VS the Vaterra V100s:
There's something worth suing over!