When I wore hiking boots on our first Camino hike, I had endless problems with blisters. My boots were definitely broken in--I had just hiked the last 60-miles of the John Muir Trail. Both Ralph and I switched to trail runners in about 2005 and have worn them on the LePuy route, Arles route, Porto, Camino Mozarabe, and about 90 miles out of Geneva-- all told probably 1,500 miles. Almost all of these trips were in the spring. We also completed the 2,650-mile Pacific Crest Trail--which includes river crossings, snow, days on end of rain in Washington--in trail runners. The PCT's terrain is much rougher than anything you will find on the
Camino Frances.
Yes, they get wet, but boots get wet too and take much longer to dry. Even if your shoes are wet, you can change your socks and keep your feet reasonably dry. If the mud is deep enough to be classified as "boot-sucking," which we have had many times in France and southern Spain, boots are even heavier to lift out of the mire.
There have been times that I wished I had boots, but overall, they have been much better for us because they are lighter and cooler. Ralph wears Asics; I wear men's (because they have a wider toe) Brooks. They are not waterproof--we like the fact that they breathe well.
We definitely carry hiking poles--not particularly because we fear turning an ankle, but because they add to our general stability on hills and any stream crossings. They also give your lower body a break and exercise your upper body a bit.
That said, everyone's feet are different and what works for one may or may not work for another.
Buen Camino
Susan "backpack45" Alcorn