Anything as subjective as this will divide opinion, as the comments show. I like it, especially as it has rounded edges.
I doubt Apple would extend the Watch Ultra's design language as completely, but I would like to see some elements make it into the iPhone Ultra. They would have to add functionality, like more battery life. I'm not sure what "more rugged" would mean for an iPhone. Most damage is related to glass, not metal. But the watch protects against that with a lip, elevated slightly past the screen. Would Apple do that? I'm not convinced.
But if they want to make a phone that is waterproof to 100m, then fine by me! Would I (or anyone) ever need that? Most likely not, but so what? It would be cool! The world is full of guys with expensive diving watches that never get wet, except in the shower...