I agree with srk, increase the number of short balls available to bowlers especially in tests. Maybe 3 an over. Its ridiculous how flat the wickets are these days, theres not really a fair contest between bat and ball. I think someone said that a bowlers are meant to bowl at the stumps but I disagree with that. Thats why there are other dismissals apart bowled and lbw and most seam bowlers bowl in the channel outside off. The bowlers job is to get the batsman out, and why protect batsman weak on the backfoot. They already wear a lot of protection.
Another rule is over throws off direct hits, penalising good fielding.
Someone said, the non striker backing up before the ball is bowled. The first time this happens, the batsman is given a gentleman's warning and if they persist, they can be run out.