When I read the a couple of the discussion threads there were posts that outright said that person X intended to develop a custom ROM based on the usual bases (e.g. AICP). Unless OnePlus does an about face on their policies seen with the 3 and 3T their devices for all intents and purposes these phones are the new Nexus line. Oneplus have unlockable bootloaders, publishes their code, use Snapdragon processors and are almost unbrickable. Heck with their last two phones you don't loose your warranty if you unlock the bootloader and install a custom ROM.
Unless their is some nasty surprise either to those development policies and or to the hardware itself I'll be unlocking the bootloader within the first hour after proving the handset works simply to avoid the user data wipe later on. That even before a recovery image is available (e.g. TWRP).
