In name only my friend. There is nothing more "amiga" in HyperionOS than what's in MorphOS or AROS. The legal argument doesn't impress me and it has nothing to do with the product or it's design. If Amiga Inc licensed the name to a dildo manufacturer, would you have the same feelings about a dildo with a boing ball logo attached to it?
Even if you own a Mercedes 500SL and in a court case you settle to hand it over to your divorcing wife (let's say she is called Brenda), the change in ownership doesn't turn the car into a "Brenda 500SL" It will remain what it is, a Mecedes 500SL.
AmigaOS is not called AmigaOS because it belonged to Amiga-Inc. (Delaware or what not).
Is like saying that since Commodore bought Miner and Morse company than the OS became "CommodoreOS" as soon as a new version was made by Commodore (ie:2.0/2.1/3.0) by other people not related to the original Amiga group from the early 80s. (utter Nonesense).
There is a Chronology, a Sourcecode, and the fact that the only evolution that original sourcecode (that dates back many years) , is called AmigaOS4 and only Hyperion can developt it and sell it.
AmigaOS is now in the hands of Hyperion as it was in the hands of Amiga Inc before and as it was in the hands of Commodore even earlier
(all three were not the original creators of the OS but they were entitled to further develop it and sell it in their due time).