This is what is putting me off with the talk of the Exynos heat issues. I also read the modem was poor in the P7 which the P8 is rumoured to be keeping.If the P8 is P5 sizing it could be tempting but I'm skeptical of the Tensor chip having been burned (pun intended) in the past with Exynos poor battery and heat issues.
Might just end up swapping the battery in the P5 and keep it going for another year.