OLED, as a technology in itself, is not necessarily susceptible to burn. If it were, my TV would be rooted by now, as it's used for hours and hours on end with static on-screen menus and HUD elements without any hint of even mild temporary retention, let alone burn. Alternatively, my MacBook Pro suffers from horrid IR on its LCD panel, so go figure. Some OLEDs may suffer, but some clearly don't. My advice would be to wait and see what unfolds before panicking
On the subject of TrueTone etc. I would imagine that the video profile of the screen will be very much under the control of Apple. I do not think we are going to see nasty blue-shifted whites and over-saturated colours on any panel that Apple uses, even if the exact same identical panel in a different application may exhibit those traits. My hope, and indeed realistic expectations of an OLED equipped iPhone, are that it will look much like my iPhone 7, ergo fantastic, but with true infinite black, and all the benefits that come with that.
In short, I don't expect any negatives from the switch from LCD to OLED, and I do expect many benefits, including infinite contrast, and undoubtedly better energy efficiency. Of course time may prove my confidence unfounded, but until then I'll just wait, instead of complaining about something that hasn't happened yet
