1. You have a increased risk of missing. 2. Waiting for him to stop moving meaning he is up for longer. 3. You are putting more risk of your swordbearer dying. 4. On the second down of each sword, you are risking crota running off to either side and missing a huge amount of dps. Pretty much if you don't have tracking. All you are doing is adding risk with no reward. It only increases your chance of failure.