Matt H sums up the main point

Bill Syndes and his 'PCJnr' ideas killed the A600/A1200
I mean, we are getting use out of PCMCIA now, but it was a (very expensive) white elephent then. The money should have went on fast ram/processor. And they should have had high density floppies and a slimline CDROM slot.
And Mehdi Ali scuppered research money for AAA.
quoting Haynie 'revolutionary if released in 1990, pretty cool in 1992, ok in 1994' -bang goes your 16bit sound, chunky, and HAM10, 24bit hybrid mode, 4mb floppies etc.
Other things i'd change:
--Release the A500 first, give Atari and the other formats a severe kicking earlier on.
--Realise the Amiga is the only egg you have left in your basket, and throw money at it.
--Realise your mid way between consoles and PC's (for wedge Amigas at least) emulate both, buy the best games developers (get some exclusives), make sure you have a good office suite.
--Stop making them baige boxes! your not a PC manufacturer, your used by artists, musicians, gamers and hobbyists. Stand out from the crowd!
--If your going to update to ECS, make it worth updating to.
--Don't sack the original Amiga team, they had more good ideas in one product than commodore had in it's whole history. Some of the stuff Mical and Needle went on to do, we could have had!
But really, If we could change history, i'd have commodore not getting hold of Amiga at all. They did not understand it or promote it enough, or spend enough money on its development.