This is exactly correct, IMO. Willpower tanks have basically Zero endurance issues, once you level past a certain point.
HOWEVER, you also have zero endurance protection. In practice, what this means is that sappers, Mu mystics, Shockers and like will drain your endurance down to zilch and you will swiftly experience toggle cascade failure and face-planting.
I find this to be an issue primarily when playing solo. If you regularly team with groups that have solid support (kinetic or what have you), it's really not an issue. When it does happen, I have resurgence on a 2 minute 15 second toggle, so I can just get right back up again.
Apart from that, I love Willpower. Absolutely one of my favorite armor sets! 👍