Everything Clive worked on was about optimisation, he was obsessed with elegance and simplicity.
I wish he had made his ZX2000 in 1999, he was speaking about things which we now see in iOS/Android.
I suspect he would have gone for ARM too due to the low power use. Shame it never happened, I guess he was worried it would not sell, but just his name on it and the fact the internet was there to spread the word would have done wonders for sales.