The recent discussion about filtering out command completions by mode
reminded the problem that while icomplete shows the most recently used
commands at the top of the list for M-x, trying to see a complete list
with TAB changes the order of displayed commands, i.e. in icomplete
there is one sorting order by recency, but in the *Completions* buffer
alphabetical sorting order.

This code puts the recent commands at the top as well,
but probably it needs to be opt-in: