I am not sure malleability is really the core issue... the core issue is that there are many different approaches to making a feature with different trade offs

I am not sure malleability is really the core issue... the core issue is that there are many different approaches to making a feature with different trade offs and costs that are not readily apparent at the outset. Not to mention that poor design upfront causes a plethora of issues down the line if you need to scale it.