A1200 was not thought out properly, a SIMM slot costing 50 pence would have allowed users to easily double the speed of the new fashionable Doom style crap popping up everywhere and if Akiko was on the motherboard too thats 50% for Akiko and 100% for CPU speed increase for the price of a 512kb SIMM purchase compared to what we were stuck with. And luckily for us because Amiga games were so badly programmed most of that increase in speed is automatic.
A SIMM slot doesn't do you any good without a RAM controller to go with it.
And there was no "fashionable Doom style crap popping up everywhere" because Doom came out a year after the A1200.