In a similar vein to the poncho-tarp combo...
I recently came across a web page showing how to make an old-style travelling cloak -
It struck me that this would be much easier to put on or remove as often as you like, to walk through a light shower, as a wind barrier, or to regulate your temperature, etc. Pulling on waterproof trousers and unpacking a hat and a rain shell can be awkward and takes a few minutes.
But with a hooded cloak, whip it out and sling it over, fasten it at the neck and you're done. You could do all of that without stopping.
For windy places it would flap, and you'd need a few buttons up the front (effectively, to turn it into a poncho). On hot, still days it would be cooler than a poncho because you could leave it open at the front.
So I experimented with a bed sheet, and it really is very easy. I thought, why not double it up as a bivvy. The scots have the patent on this idea of course - they slept in their 'great kilts', and wore them by day.
So how about it? The modern version of the old travelling cloak? At night, simply wrap yourself up in it; and maybe add a few buttons to close it, and a head-tent/headnet.