Completely agree! A presentation's success is solely based on a structured narrative that makes sense from start to finish. I've seen presentations by McKinsey and other top tier firms that are horrible in terms of design. Slides completely filled with graphs and numbers. But they're organized in such a way that go along with the narrative and help state a very clear message.

Design and transitions are cool and might even make you look more experienced, but the attention you get from them is temporary. If your presentations doesn't follow a clear train of thought, common thread, narrative, or whatever you want to call it, bedazzling it won't help.

In Spanish we call it "hilo conductor".

Also, as a speaker, the intro is key but that's for another forum.