Instead of just going in for attacks, decide what you are going to do with quick draw during the first few necessary frames of charging, where Ike brings Ragnell up, so you can better react you your opponent. Instead of thinking "I'm going to grab/attack/up smash/shffl/tech to shine/whatever" look at what your opponent is doing and then decide. One thing I notice is that a lot of low level players, or people unused to fighting Ike, will immediately go into shield when they see quick draw which just gets me fun grab combos. Players who are better or have more match up experience tend to react in ways that either force you to jump out early, or you have to chase them with an aerial instead of using the attack/grab/whatever. This should help with just using quickdraw over all.
Regarding your actual question, the QD attack is susceptible to being shielded and crouch canceled. In these instances if you are dead set on using the attack make sure you are using the auto attack by holding A instead of using the manual attack. The auto attack hits as soon as the person is in range which maximizes your distance from your opponent and makes it a little less likely that you will be punished. Be aware the auto attack has less damage and knock back than the manual attack. In some cases this leads to better/easier follow ups, other times it just isn't what you need.