There's a lot of iconic problems Apple has had with product launches in the past (attenna-gate and butterfly keyboards are some of the most obvious recent ones), but I cannot for the life of me understand how something like this slips through in 2023. They must have a thermodynamics team that helped engineer the chassis, and the SoC team must know the thermal output of their chip. Did they just not test the device?
It depends on how youre using it and what youre actively doing from what ive seen. Its common for it to get hot for those doing the initial, just bought phone and transfering data due to the amount of data transfered between devices.
The other way people see it is when gaming, one reviewer I believe had the phone throttle while playing genshin impact, and heavier gaming is becoming a bigger marketing tool for Apple recently, as its actively advertising Resident Evil on its phone, and theres a few more devs coming along too. While phone gaming is a minority in cellphone use cases, its actually considered the largest paying base when considering the entire gaming industry.
Physically, i think the other ones were that the phone is more fragile (can be broken with bending with only hands), and the phones with darker colored titanium edges gets its paint scratched off easily.
Titanium is very sensitive to scratches, just telling people as anybody who used an Essential PH-1 could tell you (I didd for 4 years)