HTC M8 == One+
I'm claiming it right here. The M8 will be to the One what the One X+ was to the One X.
A slight upgrade in specs to match current flagships, some small fixes and a pricebump (or actually, back to the starting price). It's not going to be a hit, not going to be unbelievable and most of all: it's going to fizzle out because it will be outdated quite fast after launch.
I hope I'm wrong, but this feels like a major deja vu.