Off course we are talking about this with hindsight..
I think discussing about how with a few tweaks the Amiga could have been a much more impressive machine is okay...
Sandruzzo thinks that fast ram could have done it, and I think the more wide sprites plus better parallaxing capabilities might have been amazing.
I think these two things are the weak points of the OCS, since the C64 already had 24 px wide sprites, and dual playfield might be a nice addition to the Amigas capabalities, but having 8 colours in the background and 7 in the foreground is a bit of a waste. 4 bg + 15 fg would have made some very accurate arcade conversions possible.
In the end the OCS Amiga is what it is, though, and there is no changing that-