I clearly can't match people and aimbots in 'gun and run' matches, so, I would usually take a LMG, unfold the bipod and lay down a curtain of fire in a choke point and attempt to get as many kills as possible. It can work well at times.
I doubt if my improvement in accuracy and speed in movement would improve dramatically with more practice. My improvement would also need to improve as would the need to flank enemies. Thus, I will play to my strengths and minimise my exposure to scenarios that show up my weaknesses.
I think in this iteration of Battlefield, there are more people with aimbots. There are also very good players around who have played 500 hours or more and are phenomenal. It is hard to tell.