I don’t think they’re powerful at all. They can’t do their only job well(capturing Freeman) and in Black Mesa you kill a lot more of Marines than in the original game. They plan complex ambushes to the player that fail terribly, when in the original game they’re more busy fighting against aliens(Although they do hate Freeman, but just don’t have time to pursue him) The only time the Marines ambush Freeman in the original game they succeed(Apprehension). They aren’t as dark and misterious as they were in the original game, they were really badasses there, now they look like the typical villains from the movies, they’re too dumb. Maybe it’s because the BM team tried to make them more “human”, but they’re not supposed to be human, they’re killing innocent people, they’re some ice cold motherfuckers.
I really liked the original marines, they almost didn’t talk, they were never in big groups, so this made them look more courageous and brave, and they had no emotions. It seemed that they were not even humans, and killing them was funnier because of this. But BM changed the atmosphere of the game as a whole, making it more realistic and less mysterious and mystic. And in the way the Marines lost some of their magic to fit in this new game style. Anyways, if you ask me, I still prefer the old marines.