Though one, but let's give it a go.
First of all like AmigaNG I would ditch the plan for a USA HQ.
UK and Germany, combined with the Netherlands was by far the better option.
So I would have the UK as HQ, Germany for production and distribution.
Netherlands also for distribution to like North and South America, Asia and Australia, while Germany focuses on Europe.
I also would have started with finding partners and get them on the inside working with the Amiga team, like GVP, Phase 5 and all others.
After the A1000 I would have skipped ECS for the A500 and went for AGA right away.
They were already drawing up the plans in the early 80's.
I would have more focus and ideas on Workbench, keeping it fresh and modern.
I also would have fitted every model with at least 4MB's of fast ram and got rid of the 2MB chip limit.
Following the market with the introduction of new memory modules, I would have integrated these in newer models right away.
Straight away I would have combined chips into 1 chip, start making it smaller and if possible cheaper to produce.
With the introduction of newer pc's I would have integrated those connectors and bus bridged to the Amiga side, making it also capable of running DOS and later Windows.
With the introduction of CDROM I would have fitted every model standard with CDROM.
For the top models like the A3000/4000 I would have stuck to towers like the A3500 and A4000T.
The top models should have gone with the pc standard, thus making PCI the standard bus later.
Of course sound was what an Amiga was very good at, so I would have made it with the better sound, from 8 to 16 bits and then to 24.
Maybe even do the impossible and make it 32.
Following the pc trend, I would have started moving production to Asia and then press on with graphics and sound.
Then just maybe, things would have looked a lot more different and the Commodore Amiga might have been alongside the pc just like Mac's do these days.
Maybe even better, but I would have doubt it, Microsoft Windows and Office and all others software was a far bigger success than anything else and Workbench would have had to do a lot better than that.