Well, Captain America isn't really entirely balanced as a character in terms of traits, as he's generally a protagonist character and benefits from that from a meta perspective. In an RP setting like this there's no protagonist character who has a ton of strengths to a small number of weaknesses and can take out tons of hostiles without being challenged much, which is why I wouldn't recommend ripping the powers directly from a character like that. It's better to focus on being great at one or two things than trying to be great at everything.
Personally if you're focusing on combat the speed and reflexes might be the most beneficial as they can help prevent you from taking damage.