Nope they have not ruined it. You obviously haven't been watching the same show. Original Team Arrow (Oliver, Diggle and Felicity) + Olicity have made this show. With the stunts also. I would say yes Felicity liked Oliver then, but he liked her also. So you labeling Felicity as the only one with the crush is wrong. You can see when ever they focus on Oliver and Felicity + Original Team Arrow their ratings are awesome.