AI is nothing but a marketing term for things that have existed for ages. The iPhone already has tons of AI just like every other phone has for the last decade. Siri has been AI from the start, the camera does tons of AI since ages, IOS does tons of AI stuff all the time.
We just didn't call it AI, because there's NO reason whatsoever to specifically call it AI.
Hahahah!... It's called ML (Machine Learning), and ML API has been around for several years already.
In this case, AI has become a cliché name for an internet Bot. It's not built into the phone, it needs the internet to work. So every single query you do goes to the internet and someone is keeping track of it.
What Apple wants to do, is to built an AI bot into their devices and avoid internet dependency as much as possible.
Recently they discovered a way to store information is a fraction of space commonly used. So while they may be late to the show, they will get a big spotlight. Same as with the Vision Pro, just wait until Friday and you will see.
Regarding the design of the iPhone, imo this is the best design so far, it started with the iPhone 4. Later they tried changing it with the iPhone 6, but finally returned to this design. It's the best for the antenas too.
I would say: if it works great, don't change it, don't try to fix what's not broken.
But there's always a chance Apple may surprise us in the future with a new design we didn't expect to see.