#1 critical and glaring issue of iPhone, irregardless of how good it may be:

1. Screen is too small— iPad Pro is waaaaay bigger and waaaay better!
2. Speed and power: assuming the newest M-series chip ,,, like the M4 in the new iPad Pro,,, probably at least 10-12x more powerful than even the most high end A-series pro iPhone smartphone chip. It ain’t even a fair comparison — essentially a desktop series processor (M4)— leap years ahead of even the newest A-iPhone chip! (A18 Pro)