I don't think doing an acid wash after the concrete has cured for a few days (or longer) is really going to produce an immediate large noticable result. It sounds like a good idea, but it isn't as easy, or as immediate as it may seem.
My deck is exposed aggragate, and the "exposing" is done primarily by acid washing, rubbing with a broom and power washing the concrete while its still workable. After it was said and done, a few days later I noticed a few areas which really needed a bit more concrete removed between the pebbles. So I got me some muriatic acid and went after it. I scrubbed and scrubbed and even used full strength MA. It was not easy in the least! And it really didnt make any noticeable difference at all in my case and the concrete was only about a week old.
You can give it a try of course, maybe try a small inconspicuous spot to start and see if its worth it to you.
I know you arent going for exposing the aggragate, but still, I belive removing enough of the concrete to make it less slippery is going to be a chore.
I am also attempting to resolve light scuff marks on the surface of the some of the decking. the contractor states once cured they will no be visible, I have my doubts. they also said a light acid wash would provide a less slippery deck. Why do I have the feeling we are going to have to demo and re-pour some of the deck. The marks were caused by the hose dragging across the deck, they said not to worry and it's normal.
No color, just regular gray concrete. Well that's good news, you can't feel them, they appear to be just on the surface. I figured one cured the deck will be white and they would be gone, well at least I hope.