Wow Factor?
Yes, Apple may well need to make a new smartphone that does something impressive to get back its leadership.
But a phone that isn't rectangular? Computer and smartphone displays are rectangular because they're most useful that way. A round display makes sense on a smartwatch because it is most often used to display a clock face, and similar criteria may apply to dials on automobile dashboards or in airplane cockpits... but a non-rectangular smartphone would be gratuitous and destined to be a flop.