I am having a similar issue as OP: Asus ROG GL702VS – i7-7700 / GTX 1070 Mobile. The temps do run up to 80-82c full tilt but are within normal operating range of this mobile CPU and GPU. Nevertheless, I purchased an external laptop cooling fan on the CPU side that lowers the temp notably (5-10c). There are no BSODs on crash, total freeze, hard reboot. No other games are having issues, i.e., Witcher III, Elite Dangerous, Overwatch, Diablo III, Path of Exile – all good. This is unique to GW2 for sure.