Never understand why you/others place so much significance on the Paula chip? It was just one of many components that made up the machine, yet some people seem to consider it THE defining feature of the platform. I don't think Paula was the amiga's most famous or 'killer' feature by a long shot. The chip was outdated and CBM were slated for not replacing it when AGA was released.
Amiga fanatics always place too much emphasis on the chipset.
Personally, I was always more impressed by the Motorola 68K processor.
By the time the '040 and '060 processors were introduced the low bandwidth of the chipset (better suited to the relatively slow 68000 processors in the 1000 and 500) was, in some ways a hindrance.
And, sorry, but lets be honest, the long overdue AGA graphics enhancement was not that big of an improvement (a bit slow and cumbersome).
The Amiga, with its fixed function chipset is old technology.
Today's hardware has more flexible programmable structures.
A good example of this would be modern GPUs which have come to resemble massive programmable parallel processing units.
Were you to design a modern Amiga, it wouldn't have much direct relationship to it predecessors as you'd want to take advantage of the massive improvements that have occurred in electronics in the intervening decades.
So, definitely NO, a Paula is NOT required (and can be easily emulated via software if desired).