I don't think it has much to do with player skill in this case. Near the end of Cyseal, you have enough diversity in skills to be able incapacitate the strongest opponents in any given fight before they get a chance to act. It doesn't take much skill or planning to most fights from that point onwards.
The Source Difficulty mod has a smarter approach to this issue by rebalancing SPD/Willpower/Bodybuilding/skills for most enemies so they would not be trivial to remove from combat. I expect Larian to take the same approach to their "harder" difficulties as well.
That was another area when playing with all the #'s was I took a -5 on our guys initiative, so they don't always start first. Pretty amazing how resourceful your players can be, instead of us getting all the hits in first and a large advantage, them getting their knocks in first sometimes, makes it start out seeming hopeless, but our guys are resilient and after the end of the fight you feel pretty satisfied.