In my opinion, no. People without a Fantasmic dining package line up 45 minutes to 60 minutes, some even 90 minutes prior to the start of Fantasmic. If you get seated on time and your dinner takes an hour, that only leaves you 20 minutes to get to the show and you probably won't get seats, or seats together at least.
What time of year are you going? If you are going when F! is offered every night, that will certainly be in your favor because the F! crowds will be lower. If you are going when free dining is NOT offered, you could try showing up for your ADR earlier in hopes they can seat you earlier.