Perfect flight with broadheads should trump all else, providing it is enough momentum for what you are intending to shoot. But, in your hypothetical situation, I'd pack up head to the woods if the season opened tomorrow morning. But, I'm never convinced the stars will all align properly and I will put the arrow exactly where it is supposed to be IN EVERY HUNTING SITUATION! Maybe deer are not heavy, large-boned creatures, but they have escaped far too many marginal shots, "pretty sharp" broadheads, etc.
Your situation implies it is a new setup and that you(or whoever)are not convinced which direction to take(maybe a newer archer, new bow, or whatever). In such a case, and if there were time to work on a heavier arrow with more weight forward, I'd be looking into it.
Even before I read Ashby's reports, I never felt an arrow less than 500 grains delivered like I wanted. He's taught me a lot since, and I believe it. 20-30 years ago, I shot 550-700 grains out of 60-75#. This week, I'm hunting elk with 670 grains out of 56#, and about 18% FOC. There are lighter arrows that will fly out of this bow, but I like how these work.
45# is certainly adequate weight for deer. My feeling is there is a 500 grain+ arrow combination that will work for it.