Re introducing ":="
"But then people complained that not only was it two keypresses instead of one, but it also involved finding the shift key - adding "short hand" to programming languages has a long history."
On a recent personal project which involves the manual entry of lots of time stamps, I decided to drop the colon mainly because it requires shift. I simply use HHMM format rather than HH:MM.
It's my data and if I want to use it in other applications which expect a colon, it's a simple enough matter to let the computer do the work (via an extra workflow step, if necessary).
There, saved myself a lot of keyboard work, and a useful by product is less typos which need correcting.