I don't think hp are higher than in 4E; combat just takes fewer rounds.
This depends on classes. The Barbarian and Fighters have d12 and d10 hit dice, like before. The Clerics kept their d8's but the rogues moved up to d8's and the pure arcane casters moved up to d6's. That's an increase.
The stat system allows for CON to be a bit higher overall, with increased bonuses to each races stats, although I don't see too many characters with higher CON as a result, since CON is pretty much always a secondary stat. As CON also acts as the stabilization roll stat and the level at which death occurs, its role has been enhanced.
The Favoured Class system allows an additional hp per level. Although our group is more partial to skills, most commentary indicates anyone at the d6 level pretty much always takes the extra hp, and probably most d8 classes do as well.
I don't think hp have increased markedly, but I do think they have increased.
STR enhancements are a lot more common, which increases damage. OTOH, my 1/2 Orc Barbarian, L6 in 3.5 dropped -6 to hit for +6 damage last game - in PF, he can only get +4 (with a -2 to hit) from Power Attack. He'd be no stronger in PF.
I think there are broader abilities to increase damage and/or obtain more attacks, though, so I would agree the characters' ability to inflict damage has been enhanced.